This is a wonderful piece of work. It makes a relatively complex thing easier to understand, without dumbing it down. Excellent eductation going on here.
Oh it is dumb as hell what this show spews. Open your eyes we are stationary. For millions of years we chase a sun going 500k miles per our as we go around it at 66k miles per hour and spin at 1,000 mph at the equator. We still see the same constellations with no parallax. In winter say we are at 3 o'clock and in summer we are at 9 o'clock, right window left window yet the same view. Bullshit Can't work
There is no tide on Earth Tides are long waves across the oceans. They are caused by the gravitational force exerted on the earth by the moon and to a lesser extent by the sun. Wiki. In fact, tides are an artifact of the up and down movement of coastlines in a stable ocean, caused by thermal expansion of the earth's crust due to sunlight moving westward. Some coasts have no tides, some have only one tide, some have two tides, and some have four tides per day. Tides vary in height from 0 feet to 50 feet and move at different speeds and in different directions. It is impossible for the moon's gravity to cause tides. Do you agree?
The music is very distracting and loud on headphones. Only saying this because otherwise this is a fantastic explanation! The animations make it so intuitive, appreciate all the work and I hope you make more. Thank you!
Science teacher and long term sailor here saying Thank you. What a great explanation. It cleared up a few points I couldn't quite get. Excellent education.
The very best explanation that I have seen. I understand the science and I watch certain vids to discover who does not, or cannot explain the science. You clearly know, and you can explain.
Just for future reference: the Bay of Fundy, with its funky resonance, has a counterexample. The Gulf of Thailand experiences one teeny tide per day. Very weird if you're planning your diving or navigation.
@@Waterlustsurely, in order for the water to be "left behind", then the earth would have to accelerate quite quickly TOWARD THE MOON. How can that be possible if the earth gravity is "six times stronger" than the moon's?
@@waynemoore8615 the rate doesn’t matter as much as the difference in rates. The difference in accelerations between Earth’s core and the fluid on its surface is very small, but because water can flow so easily and the ocean’s are connected, that small difference can produce noticeable changes in sea level.
⚖🗿The balance point of the rotating system is inside the Earth, not it´s center but shifted to the Moon. So I would say centrifugal force causes the left behind bulge. 🪐🌀🌛Atmosphere should be affected a bit, too.
@@Waterlust If you are suggesting that the moon "pulls" the earth towards it with enough force (and suddenly enough) to leave some water behind it (slightly), then the mass of the moon and earth would have had to move closer together (slightly). That would inevitably mean that: 1. The gravitational pull on each other would immediately increase, and 2. With no other force to stop that movement (newton's law), they would continue to accelerate exponentially, and collide after a small period of time.
Absolutely fantastic video, thank you. The best example of tides out there no question. Even famous "science communicators" have used the 2 bulge explanation. The only thing is - the background music is not background at all. Its way too loud. When the music pauses for a few secs just after 6:34 the video feels calmer and your voice is not overshadowed by the music. The music is okay - but needs to be much much lower volume so its barely even there. Thanks for a great vid!
That's the first time I've seen the "four little planets" explanation, or the ellipse-forming simulation. Very cool, very clear, and much more satisfying than the "traditional" explanations. Well done!
I agree. I learned this from PBS Spacetime. Their visualization was of the whole earth with connected oceans. Showing it with the tiny planets, or particles, you are clearly able to see why the elongation happens on both sides of Earth. It also makes it easier to explain to someone else.
oh boy! several misconceptions cleared up here. now I know why friends have hesitated to fully explain the tide charts and graphs to me. thank you for doing the work!!!
I thought the opposite side bulge was created because the moon and earth system rotate around a point that is located between the earth and moon, creating the 2 bulges. Isn't this true also to some extent?
A science book I read gave the most basic simple explanation I have heard. It said the moon pulls the water towards it on the near side, and pulls the earth away from the water on the opposite side. It said thats why the tides have a higher and lower high tide each day. Made a lot of sense to me.
@@wavydaveyparker , I never said it was correct. I simply pointed out that a book on science gave an alternate explanation that was very easy to understand and made sense, because two bodies exert gravitational forces on each other. It also explained the two high tides we have each day with one being a "higher" high tide versus the other. It also highlights an issue with inaccurate science information being published, and not just in this book. Here's an example: It is impossible for gravity to create a star by the current model of a collapsing nebula of hydrogen gas. Gravity simply can't pull the gas anywhere near tightly enough to form a star. The heat would easily overcome gravity as cause the gas to stay dissipated. Ever opened a tank valve at 3,000 psi, and seen the incredible force that the gas has, as it escapes? Charles Law precludes star formation from happening by gravitational collapse. The gravitational force causing collapse can't get anywhere near the level necessary to complete the process. Eventually the heat would easily overcome gravity. And yet, we still see this being taught as how stars are formed. Then we have the issue of planet formation. That doesn't pass muster either, but I won't go into that. My point is, even accepted science being taught at the highest levels, in books other than the one I mentioned are not always accurate, and yet, it is still being taught. Looks like they teach from comic books as well. I'm curious how you might explain star formation? (Academics are aware of these issues, but continue to teach them, and we blindly accept them as fact. Then, to make it worse, a "rescue device" is tossed out there, rather than simply scratch our heads, and say, "We honestly don't know". One such rescue device is this: An exploding supernova caused gravitational waves that compacted the gas tightly enough to allow gravity to take over. A child could see through all the holes in that.)
@@wavydaveyparker , NATIONAL GEOGRAPHIC had this to say about how tides form. ***I AM NOT SAYING IT'S CORRECT; ONLY THAT THE INFORMATION IS OUT THERE*** "The tidal force exerted by the moon is strongest on the side of the Earth facing the moon. It is weakest on the side of the Earth facing the opposite direction. These differences in gravitational force allow the ocean to bulge outward in two places at the same time. One bulge occurs on the side of the Earth facing the moon. This is the moon’s direct tidal force pulling the ocean toward it. The other bulge occurs on the opposite side of the Earth. Here, the ocean bulges in the opposite direction of the moon, not toward it. The bulge may be understood as the moon’s tidal force pulling the planet (not the ocean) toward it." education.nationalgeographic.org/resource/cause-effect-tides/
The ocean on the opposite side of the Earth, opposite the Moon, wants to travel in a straight line, until acted on by an outside force. That force is the Moon, so the ocean is pulled towards the Moon and travels in a circle instead of a straight line. Because the Moon's forces are "tidal", they are different at different distances from the Moon. Therefore, the Earth is stretched into an ovaled ball, like gnocchi. That's a roundish pasta. When orbiting a black hole, you are spaghettified. Stretched out into such a long line your molecules are disassembled. Not a single part of you is pushed away from the black hole. Same thing with the Earth Moon system. Not a single part is pushed away. All parts are pulled towards each other.
"Isn't this true also to some extent?" No. Tidal forces can be explained _solely_ by gravity, no inertial "forces" required*. The video is correct (as is e.g. the one PBS Spacetime made 8+ years ago). While more complicated than the arguably more intuitive "centrifugal force does it" "explanation" it _does_ have the advantage of being, y'know, right :). Anyone believing otherwise has fallen victim to one of the most widespread myths about the tides (it's even offered as the explanation in a few textbooks - though others offer the correct explanation - as well as _many_ UA-cam videos etc. so it's a completely understandable mistake but it _is_ still a mistake). If you really want to understand it though i'd suggest you don't take the word of people in UA-cam comments sections (that obviously includes me :) but instead google something like "tide physics myths" and look through the results, where you'll find plenty of articles from various authors, some aimed at lay readers, others published in peer reviewed scientific journals (with all the grisly/interesting - depending on your preference :) - mathematical details), correcting the various tide misconceptions. As one example, Prof. Donald Simanek created an excellent webpage years ago, which you can still find online, that in relatively simple terms explains _lots_ of misconceptions about physics (his article on tides specifically is called "Tidal Misconceptions"). (though - unfortunately in some ways - if you really, _really_ want to understand then, as with most things in physics, you kinda need to understand the mathematics. If/when you do you see that the equation for tidal force simply doesn't include terms for inertial "forces" and can be derived _solely_ from Newton's law of universal gravitation) * OK _strictly_ speaking, in the framework of General Relativity gravity _itself_ is an inertial "force" but while true that's _also_ irrelevant in this context because here we're using the Newtonian framework, in which gravity is a real physical force (note the lack of quotes)
A a yacht Captain who has studied tides for decades, this is the best simple explanation particularly covering geographical anomalies. I will be sure to show this to many who ask about tides in my industry. Thanks.
That was SO WELL done!!! A wealth of information in a beautifully illustrative short video. So many questions that I've had about tides became clear in a matter of moments.
I've known intellectually why tidal bulge occurs on both sides of the earth simultaneously - but never intuitively. Until now. Learning tickles, even at my age (75). Thank you!
@@oortcloud8078 Somewhere within this wretched hovel I call home is an ancient diploma granting me a Baccalaureate degree in physics. My particular interest was in orbital mechanics, so I'm already familiar with the barycentric nature of the earth-moon system. But it's been a long time, and knowing how something works isn't quite the same as knowing why. Still, I appreciate your taking the time to acknowledge this old fart's comment & sharing your own insights into the subject. All the best to you.
Fun fact: while mass is measured in kg in scientific units, weight is a force and is measured in newtons, named after that guy who watch an apple fall. There are just under ten newtons in the force exerted on a one kg mass (the exact number is equal too the acceleration of gravity). That means that an apple typically weighs around one newton. Nice!
@@wavydaveyparker almost... if you take into account microtides within any orbiting platform then the strictly weightless result only apple-ies of the centre of mass of the fruit lies on a two dimensional curved surface passing through the centre of gravity of the spacecraft. I agree totally that anywhere in board it's going to be a long way short of the one newton I claimed.
Very good video, helped me understand why there is 2 bulge of high tides. I can finally stitch together things. Previously, I found out that gravitational force on Earth by the Sun is actually larger than the Moon, then I got confused as to why the Moon affects our tides more than Sun. Upon googling, I found out that it is due to the gravitational change gradient of Moon is larger. I had to satisfy myself to that answer until now, when I can finally stitch the concepts together with the help of your animation and explanation. Thank you, from a high school physics teacher
Thank you for this complete explanation of all the tides. Both lunar and solar. I realize their are more but knowing just those and how they interact satisfies my curiosity.
This happens to be the best video to deal these topics . Brief & intriguing indeed. I hope to find another video to discuss various alignments in details.
What a wonderfully clear, interesting explanation of tides. I, too, was taught the over-simplified version of how the sun and moon cause the earth to bulge, but never why the OPPOSITE also bulges...only that it does. If they just would have mentioned Newton's discovery to us, it would have been easy to figure that out, and, I would have understood why the moons of gas giants have a hard time surviving. Now I understand! Thank you for that knowledge!!!
What a wonderfully clear and interesting comment. Yes, Newton firmly established that a common centre of gravity was a prerequisite for all celestial bodies in motion. This wobbly inertial movement is definitely the main cause behind the tides, although it still required the insights of Laplace to complete the picture. Thanks
Gteat content! There is more. The moon varies in its orbit from north to south snd back again which gives us the difference between tide extents - meaning the high tide is higher than the next high tide, and the low tide is lower than the next low tide when the moon is not orbiting at our equator, but is rather orbiting north, or south of it. If you’re a surfer, this is very interesting and useful.
What's amazing is that something as ancient, familiar and well-studied as the tides, still have more that can be learned about them. I think this video came up in my feed because i have been researching the size of ancient tides going back to when the moon originally formed. I saw a post on Quora complete with math that suggested ancient tides were over a kilometer high. Since its formation, the moon has been slowly spiralling outward from the Earth and slowing its primary's rotation in the process. Not only did Earth have tsunamis of water sloshing around every few hours but likely also tides of lava oozing from the partially cooled and tortured crust. Would love to see a video about Ancient Tides of the Early Earth. We look at the moon as a beautiful and peaceful symbol of serenity but in the early years of the planet, it was more like a blender. A blender powered by a chainsaw.
In an above comment I did a quick calculation and estimated the Roche limit is about 15,000 miles, which is where the Moon formed. Perhaps 16,000 miles. So, that's 4 times the Earth's radius, so orbital period would be 4 to the 3/2 power, which is 4 times 1.414, which is about 5.6 times greater than the ISS's 1.5 hour orbit, so about 8.5 hours. Oh, crud. The Earth was rotating about once every 4 hours. Shoot. Well, I guess the tidal "wave" would come by about twice every 4 hours. Dang, that's fast! At the equator, that's 25,000 miles per 2 hours, about 12,500 miles per bour.!
As a kid I'm the 1960's the tides were a huge part of my life, even in winter, we lived right on the coast of the northeast Atlantic, those deep green waters are in my blood.
Great work, I'm a kayak instructor and the over-simplified "two bulges" diagram is such a massive sticking point when teaching tide theory. Thanks for going the extra mile, will definitely be sharing this with students.
I wish you wouldn’t Mr Waters, because this isn’t how the tidal waters work. Please stick with Newton’s Equilibrium Theory first, and then move onto the Dynamic Theory, which was discovered by Euler and Laplace.
This has been the best video about tides i've seen so far. However, it still sticks to the idea of two (or more) bulges circling our planet in pretty much one day.
@@Waterlust EINSTEIN IS UNCOVERED AND OUTSMARTED BY FRANK MARTIN DIMEGLIO: WHAT IS E=MC2 is dimensionally consistent, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. Indeed, consider what is the man (AND THE EYE ON BALANCE) who IS standing on what is THE EARTH/ground; AS touch AND feeling BLEND; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE). Indeed, WHAT IS GRAVITY is, ON BALANCE, an INTERACTION that cannot be shielded or blocked. GREAT. BALANCE AND completeness go hand in hand, AS it all CLEARLY makes perfect sense ON BALANCE. Magnificent. By Frank Martin DiMeglio The sun's tide-generating force is about half that of the moon. One half times one third is one sixth. Consider what is water. The density of what is the Sun is believed to be about one quarter of that of what is THE EARTH. The diameter of WHAT IS THE MOON is about one quarter of that of what is THE EARTH. The density of the human body is about the same as water. Lava is about three times as dense as water. Pure water is about half as dense as packed sand/wet packed sand. We can multiply one fourth times two thirds in order to ALSO get the surface gravity on the Moon in comparison with what is THE EARTH/ground. The gravity of the Sun upon the Moon is about TWICE that of what is THE EARTH. The lunar crust is about TWICE as thick on the far side of what is the Moon. Notice what is the TRANSLUCENT AND BLUE sky ON BALANCE. The maria (lunar “seas”) do occupy ONE THIRD of the visible near side of what is the Moon. One half times one third is one sixth. What is E=MC2 is taken directly from F=ma, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. Consider what is the orange AND setting Sun ON BALANCE. Consider what is THE EYE ON BALANCE. Consider what is the fully illuminated AND setting/WHITE MOON ON BALANCE !!! What is E=MC2 is dimensionally consistent. The land surface area of what is THE EARTH is 29 percent. This is EXACTLY between (ON BALANCE) what is one third AND what is one fourth. The maria occupy one sixth of what is the Moon. The BULK DENSITY of what is the Moon is comparable to that of (volcanic) basaltic lavas on what is THE EARTH/ground. Consider what are the tides. ONE HALF times one third is one sixth. ONE QUARTER times two thirds is one sixth. What is gravity is, ON BALANCE, an INTERACTION that cannot be shielded or blocked. CLEAR water comes from what is THE EYE (ON BALANCE). ON BALANCE, what is THE EARTH is ALSO BLUE !!! GREAT. BALANCE AND completeness go hand in hand. What is LAVA IS ORANGE, AND it is even blood red. Awesome. Yellow is the hottest color of lava. Blue is the hottest flame color. Note: Consider what is the blue flame. The lunar surface is chiefly composed of pumice. Volcanic ash is present as well. The topologic range (lowest to highest spots) on what is the Moon IS about THE SAME as that of THE EARTH (i.e., about 15 kilometers). This is the approximate distance from the very bottom of the Marianas trench to the top of the Himalayan mountains. Magnificent. The bottom line: What is gravity goes way beyond what Einstein tried to lay claim to (and to descriptively isolate). That is abundantly CLEAR. He never nearly understood what is TIME. By Frank Martin DiMeglio In understanding SPACE, what is gravity, TIME, AND time dilation (ON BALANCE), it is important is it to understand what is a BALANCED displacement of what is SPACE. ELECTROMAGNETISM/energy is gravity ON/IN BALANCE. Consider what is E=MC2. TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE. Consider TIME AND time dilation ON BALANCE. (c squared CLEARLY represents a dimension of SPACE ON BALANCE.) Indeed, the stars are POINTS in the night sky ON BALANCE. The rotation of WHAT IS THE MOON matches the revolution. Consider what is THE EYE, AND notice what is the TRANSLUCENT AND BLUE sky ON BALANCE. NOW, consider what is the BALANCED MIDDLE DISTANCE in/of SPACE. CLEARLY, BALANCED inertia/INERTIAL RESISTANCE is fundamental (ON BALANCE). “Mass"/ENERGY IS GRAVITY. ON BALANCE, consider what is the orange (AND setting) Sun. “Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent WITH/as what is BALANCED electromagnetic/gravitational force/ENERGY, AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE (ON BALANCE) consistent WITH E=MC2, F=ma, TIME, AND time dilation ON BALANCE. This CLEARLY AND NECESSARILY represents, DESCRIBES, AND INVOLVES what is possible/potential AND actual ON/IN BALANCE, AS ELECTROMAGNETISM/energy is CLEARLY (AND NECESSARILY) proven to be gravity (ON/IN BALANCE). Notice what is the fully illuminated (AND setting/WHITE) MOON ON BALANCE. Great. TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE. Indeed, inertia/INERTIAL RESISTANCE is proportional to (or BALANCED with/AS) GRAVITATIONAL force/ENERGY; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE). This CLEARLY explains what is E=MC2 AND F=ma ON BALANCE, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE !! (Consider TIME AND time dilation ON BALANCE.) Great. Indeed, consider WHAT IS THE EARTH/ground ON BALANCE. I have mathematically proven why the rotation of WHAT IS THE MOON matches the revolution, AS ELECTROMAGNETISM/energy is CLEARLY (AND NECESSARILY) proven to be gravity (ON/IN BALANCE). Consider TIME AND time dilation ON BALANCE, AS the stars AND PLANETS are POINTS in the night sky ON BALANCE; AS c squared CLEARLY represents a dimension of SPACE ON BALANCE. (Consider what is THE EYE ON BALANCE.) I have mathematically proven what is the fourth dimension, AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE) !!! I have explained why what are OBJECTS may fall at the SAME RATE. By Frank Martin DiMeglio
5:16 decompose the vectors from the upper and lower planet. You get arrows pointing perpendicular to the poles of the planet. This pushes water out to the sides. Why wasnt this included here? Also, the COG from the moon/earth system is on the moons side of the earth, making the ‘’polar force push’’ greater on one side.
On fact you have left out is the drag or lag factor. Spring tide low is always at about 9am in the morning where I am. If you look at your illustrations of the bulge this should be at 6am when the sun and moon is rising but it takes place about 3hrs later.
Excellent presentation! As a coastal engineer I’m familiar with tidal constituents and where they come from, but this is an unusually lucid explanation of this complex phenomenon which, as you said, many textbooks still get wrong. Next video, maybe you can tackle why referring to tsunamis as “tidal waves” is just wrong!
Thank you so much, excellent video. finally a logical and simple explanation that matches actual observation of the tides, the popular explanations never sat ok with me because they never did.
Great video! One minor comment. The time for a shallow water wave to traverse the Bay of Fundy (and back) is much less than 12.42 hours. The resonance is with the entire Gulf of Maine.
The River Severn in England has a wide tidal range - 2nd only to Fundy it is claimed. This results in a tidal "Severn Bore", which I think is caused by the estuary getting narrower and shallower, so as a wave approaches from the ocean the deeper water slows down & the surface water overtops it.
While a good explanation of the "tidal forces" between objects, they are not strong enough to cause ocean tides. You have to account for centrifugal forces on Moon and Earth orbiting their center of mass. See Richard Feynman, Lectures on Physics, section 7-4.
You are entirely incorrect. Centrifugal forces are simply centripetal forces that are perceived in a different reference frame. It's like putting a camera on Newton's apple and dropping it. Is the Earth accelerating toward the apple? No. But centrifugal forces would say such a thing because of the incorrect reference frame.
@@MultiPleaserthe earth is accelerating towards the Apple in an infinitesimally small way though. That’s how gravity works. Objects are attracted to one another based on their mass. While the earth exerts a force on the Apple and it accelerates towards the ground (center of the earths mass), the earth in turn is accelerating towards the the surface of the apple (center of its mass).
Dear Dr Rynne, I understand that the Earth Moon system rotates about the barycentre which is 1/3 the way below the Earth's surface. The 2nd bulge in tides is the centrifugal effect of this rotation. The Earth's orbit is traced out by the barycentre.
@@WaterlustWhat does the barycentre have to do with the tides? Sounds like more flat earth nonsense. I suggest you research Nicholas Tesla and see whst he had to say about Einstein’s Relativity nonsense. 2) Galileo's ball drop experiment and his theory that the tides are the result of the Earth's MOTION in space and not it's mass. 3) the many followup experiments to Galileo's ball drop tests. The hammer&feather on the moon. The bowling ball and feather in Nasa's vacuum chamber. 4) the LIGO project. The detectors were PUSHED out of alignment. Not pulled. 5) Newton's Laws of Motion. F=ma. Force comes from Acceleration of the mass. Not the mass itself. 3rd law of motion, Action and Reaction. Gravity/g-force is a Reactionary force. The resistance of the mass to being Accelerated. 6) Kepler's Laws of Motion. In an elliptical orbit, as the radius decreases, the acceleration increases. This results in the annual high tide on the side OPPOSITE the sum as this where the most acceleration is occurring. The earth-> rotating on its axis creates a centrifugal force. Acceleration its mass outward and forward creating a tidal bulge as the water gets Accelerated to a higher radius/orbit. Add on the planets orbital frame and you get two tides per day as the mass is accelerated clockwise and then counterclockwise as the earth rotates in relation to its path around the sun. Just remember, m=m. It's only attribute is how much space the object occupies. F=ma is what space it occupies. As the radius increases, so does the acceleration factor causing a decrease in mass. The atmosphere becomes thinner with altitude on account of an increase in acceleration with a constant force (Earth's axial rotation velocity).
Very clear explanation, i love the part where you split the planet in 4, a very nice way to move toward a gravitational field notion. I will sure reuse it! My understanding has always be that although the maximum of the gravitation field is just 'below' the moon (on the moon-earth axis, moon side) as you explain and draw, the inertia of a body of water makes it that the actual bulge is 'late', by an amount that from memory is close to 90° so that at the end, the bulge of water is about opposite to where it is classically drawn. As it makes the explanation a bit more confusing, i tend to just add this notion after where your nice video brings us.
Super interesting, we hadn't heard about an offset between the tidal bulges and the earth-moon line caused by inertia/earth's rotation. We're not sure that actually happens, we will have to read up more on it! One point we'd bring up is that the concept of the tidal bulges is somewhat simplified since the planet isn't entirely covered in water (land affects things), and there are many "bulges" in different locations simultaneously. The classic example of the moon bulges is specific to the M2. One way we like to look at it, is that each "bulge" is a wave, and each wave is traveling around the planet. Sometimes multiple waves hit the same place at the same time (eg: spring tides), and the location of land masses can interrupt how fast the waves make their way around the planet. NOAA has a nice discussion about this at the link below...though they do suggest that if the earth were entirely covered in water, the bulges would align with the axis of the respective celestial bodies causing them. Though at the same time, just because NOAA says it, doesn't mean it's necessarily true... oceanservice.noaa.gov/facts/moon-tide.html
@@Waterlust I've not been able to find the book where i think i read the 'around 90° offset' (cause it was a borrowed paper one), only its reference so far. The wikipedia article hints at this offset by saying 'The moment of highest tide is not necessarily when the Moon is nearest to zenith or nadir' but is non commital on how much of an offset we could expect in general. The Bathymetry chapter (en.wikipedia.org/wiki/Tide#Bathymetry) gives an example of 2 and a half hour offset for Norfolk, Virginia, so more like 40° in this case. I totally agree that the coastal effect have a lot more impact (including in delaying the tidal wave), but they are also a lot more difficult to explain in simple terms. M2 bulge is the first thing to explain, but i'm just worried that drawing it aligned with the bulge in the gravity field is giving a too simple but too inaccurate result.
The tidal bulge does preceed the Moon and accelerates it tangentially, which makes it move away from the Earth and slow down. The tidal bulge also slows down the Earth's daily rotation, because the Moon is pulling back on the Earth as well. From old memory, the Earth started out with about a 4 hour day and the Moon's orbit was about 6 hours. But, because the tidal bulge preceeds the Moon by a few degrees (definitely not 90, but more like the 30 mentioned in a reply) the Moon is accelerated just like when your hand moves in a circle ahead of the rock in your sling, as you accelerate a stone in order to slay Goliath. The leather string becomes more taught and stretches as the stone speeds up and centripetal forces increase. So, the Moon moves away from the Earth because as an orbiting object accelerates, it doesn't speed up, but rather increases in orbital radius, and slows down. Right now the Moon is retreating from the Earth about 1.5 inches a year as I recall. It might be 2 cm, which is 4/5ths of an inch. Might want to check that. Anyways, it's about the speed of continental drift: slow. The Moon is currently moving just over 2000 mph, maybe 2200. But it varies a lot thanks to the very elliptical orbit. When the Moon first formed, and had a 6 hour orbit (just outside the Roche limit you talked about) it's velocity was a lot closer to the International Space Station's 17,500 mph. Equations exist for determining the Roche limit, and as I recall they are typically a ratio of radii, adjusted for density. Since the Moon's density is half of the Earth's, and it's radius is 3.666 times less, then the Roche limit is... guessing around 15,000 miles. That's a lot closer than the current 239,000 mile average. If my guess is correct, and orbital radius started out at 15,000 miles, then orbital period was about 5 times longer than the ISS, so about 7.5 hours. Tides were insaely high and very fast, and probably eroded entire continents, if there were any after the crazy impact than formed the Moon.
Excellent job! As a lifetime sailor, your info hits home, particularly around the need to listen to locals to understand. I wish, however, you have mentioned one group of people who know the tides better than anyone else in a given region: indigenous peoples. Perhaps not the why of it, but certainly the what, when, and how of it.
The best explanation of tides I have seen so far on UA-cam. I wish you had added some additional examples of where and how resonance results in high tides. For example Incheon, South Korea has 34 foot tides but the coastline does not seem to resemble the Bay of Fundy.
South Korea is a developed country, and as such it uses metric, so that would be a 10m tide, not 34 foot. There's only 3 undeveloped countries still using imperial units.
I had read a good explanation for tides before, but the video explained it beautifully and in more detail, particularly the tidal constituents and their relative timings. This is why I pay an internet provider. Also, seeing a totally unexpected glimpse (09:54) of my hometown in this video was a nice bonus.
If you want more likes, turn down the background audio to a minimum of a third of the speakers volume. Sounds more like a music video instead of a very interesting and educational video. That's just my opinion but I have a feeling much of your viewing audience would agree
Great job for giving a 80% complete explanation for the marines tides, but as I'm picky, I'm missing the "jewel on top of the crow" which would make this video really outstanding: the explanation about amphidromic points and the influence of the Coriolis force on all this moving water! You did the same trick as those videos that present the two bulges and says "too complicated to explain".
sounds like we need to do a follow-up video! We always struggle with figuring out how much information is too much or too little. Thanks for the feedback!
@@Waterlustthanks for the great work you have done here in this video- just one request in your next video please keep the music down and your voice up so I can focus on the information better. Thanks anyway.
@@Waterlust There are times, when one has to 'fib', and leave out the real/extra information, so, as to convey the concept. Add too much, and you could lose the audience, they either get confused or lose interest.
at 2:53 the statement "bigger objects create stronger gravitational forces than smaller ones" should have been worded "more massive objects.....less massive ones".
This is the best video on thie subject...I have seen many many videos on this, and none of those gave me a complete intuitive understanding of what goes on.
I grew up in Anchorage Alaska and they have the 4th biggest tidal change in the world and are number 1 for cities in the United States. Anchorage sits on a peninsula in Cook Inlet with Turnagain Arm to the south and Knik Arm to the north. The tidal change between high and low tide averages just around 30 feet and going up to over 33 feet for Anchorage and Turnagain Arm. Surfers and paddle boarders regularly ride the bore tides that occur when the tide is coming back in. They can ride the bore tide for miles if they’re lucky. But when the tide is low Turnagain Arm becomes a mudflat with just the river channels flowing through it. The mud is sticky and nasty and snags unsuspecting people in when they unknowingly walk on the mud. The extreme tides makes Turnagain Arm unusable for boats really because of its shallow depths.
I remember learning about this when I traveled to Alaska in the summer of 2022 for a vacation. We were on a train and traveling next to some of those mud flats and a tour guide was talking about it.
OMG - I spent 4 years in Alaska as a young kid(Elmendorf AFB) and always thought it was pronounced Ptarmigan after the fowl! Crazy. I guess if I had paid more attention to my Alaskan History, I would have known better. Thanks.
The Bay Of Fundy is incredible! If you haven't already seen it, you'll like the video we made on Tidal Bores that includes surfing the bore in Moncton! ua-cam.com/video/F-EoL4Jf7ug/v-deo.html
Good explanation. One minor complaint; the narration at 8:45 is misleading and seems to imply that the tidal forces vary as 1/r^2, when they actually vary as R/r^3, where, for the earth, r is the distance to the source of the tidal force and R is the distance from the center of the earth.
Yes, this a great point and something we may address in a follow-up video. It is the gradient of gravitational fields that controls the magnitude of the tide, so the first spatial derivative leads to the 1/r^3 dependence and explains why the moon is more influential despite the suns gravitational force being stronger on Earth. We missed an opportunity by not including that and wish we had.
Very entertaining! However, why do you only consider the ‘tidal force’ in linear ‘free-fall’ motion? We get the exact same results when we experience a ‘tidal force’ in orbital ‘free-fall’ motion around a common centre of mass. And its certainly safer, more realistic and adheres to the accepted laws of Motion, which were laid out by that Newton guy you mentioned, and we wouldn’t have to contend with any messy unavoidable collisions? Which wouldn’t be very environmentally sound for any of us! Anyway, I enjoyed the presentation and congratulations. Take care.
We present the context of linear acceleration as it's far simpler to illustrate to a layperson. The stretching effect caused by gravitational fields is the same whether an object is accelerating through them linearly or centripetally.
@@Waterlust That’s interesting and thanks for bothering to reply, it’s much appreciated. Maybe it’s just me, but I distinctly got the impression from your beautifully animated introduction, that you wanted to get away from the usual, boring, monotone, layperson speak, where lesser competent content creators, unlike yourselves, usually say, “there is a bulge on the far side and don’t ask why? It’s just there???” I honestly think your superbly produced production deserved better…than to just say, the Earth accelerates towards the Moon leaving water behind. It’s just a shame, when you were so close to providing the correct answer for, “why tides really happen?” The ‘squeezing’ effect on oceans - _and it’s not a ‘stretching’ effect, because water cannot be stretched_ - caused by gravitational fields is not the same whether an object is accelerating through them linearly or centripetally. If it’s linearly, then the end result is destruction and we get rapidly increasing tides. If it’s centripetally then, the earth and moon are in a balanced orbital motion around a barycentre and inertia has to be recognised, and then we can all gratefully, continue to correctly predict and experience our wonderful tidal systems every single day. However, who am I to talk? … Just someone who was taught Physics correctly at school I guess, by an extremely good teacher - but who cares! Thanks for the chat.
@@wavydaveyparker Interesting stuff! We think there can be legitimate debate regarding which term, “squeeze” or “stretch” should be used…but the overall message is that the gradient in gravitational fields, and the motion it produces, produces deformation of celestial bodies, including the tides. The idea of using the centrifugal “force” to justify the far side deformation is interesting and we’ve seen it widely used. Our problem with it is that it's a little misleading and in some cases insufficient. Centrifugal forces are “apparent forces”, they don’t explain why tidal force deformation happens in linear acceleration cases (as modeled in Matlab in the video), and why tidal force deformation is always symmetric, regardless of the celestial body or its orbit. An explanation based solely on gravitational fields doesn’t seem to have these problems, while also preserving the physics of inertia and the apparent centrifugal forces of orbits. The idea that the planet accelerates away from water on the far side is equivalent to saying the water experiences a centrifugal force due to the orbit. It's just presenting it in a different way. That’s at least our perspective on it….it’s a fascinating subject and we enjoy thought provoking discussing about it! Thanks for participating
@@Waterlust And I wholeheartedly agree, the Astronomical part of the discussion is a fascinating subject and I thank you for engaging in this thought provoking friendly chat. I certainly don’t want our conversation to detract from your otherwise excellent video, which I still think is very interesting and well made. And, at least you didn’t bring up the crazy idea of planets performing ridiculous start-stop motions and partial bulge filling, which I’m sure you’d agree is totally misleading. _I did make a daft little video about that if you’re interested? 😄 any kind support is always welcome!_ … Anyway, here’s the thing! Your first sentence summed up the confusion most people face when thinking about gravity and orbits… _“The overall message is that the gradient in gravitational fields, and the motion it produces, produces deformation of celestial bodies, including the tides.”_ The gradient in gravitational fields does produce deformation of celestial bodies in the form of tides. However, they have nothing to do with the actual motion of planets, that is the sole domain of inertia. The planets don’t move because of gravity, they move because they initially had inertia, and wish to continue in there straight line paths forever. It’s only when gravity gets involved that there motion is shaped, into what we perceive as orbits in a curved space. Now, I don’t want to get into ‘apparent’ forces and reference frames here, because I’ve been over that a jizillion times!!…despite to say, that gravity itself can also be considered as a ‘fictitious’ force. So, instead I’ll finish with something you might like to consider if you decide to produce a possible follow up video, because this is where you came so agonisingly close to being right on point! Stick with the concept of ‘free-fall’ … which you alluded to in your video. What Newton concluded and what Professor Brian Greene demonstrated in an excellent video on Relativity, was that when a celestial body is in orbit around a barycentre, it experiences a zero ‘net’ acceleration at its centre. The tidal force is caused from this point outwards. Tides are actually formed by the buildup of lateral, hydrostatic pressure in the oceans on either side…and, when I say, ‘side’ I mean near and far. However, that just my considered opinion, based on the scientific evidence provided by my teachers, but what do they know! Nothing!! … That’s what? Kind regards, wavy.
@@wavydaveyparker Interesting points, though the inertia mechanism wouldn't result in tidal bulges in linearly accelerating celestial bodies, it would only apply when there is an orbit. Though, do linearly accelerating celestial bodies have tidal bulges?…we’re not sure there are any documented cases of that. We also wonder how the bulges end up being symmetrical. The inertia argument only applies to the bulge on the far side, so what about the close side? The explanations we've seen say that the bulge on the close side is caused by gravitational attraction, while the far side is inertia, and yet somehow...they are both the same magnitude. We haven’t done the math, but that seems a little fishy. One idea we had is to simulate a cluster of particles in the way we did in the video with Matlab. Instead of using the universal law of gravitation to calculate all the forces, we could create a virtual world where the gravitational force between objects is not distance dependent (in other words, the force of gravity = G*M1*M2). In that fake world, orbits could still be maintained, and we could model a cluster of particles orbiting another celestial body. If the cluster is deformed in the way we see in real life, it would support the idea that inertia is the dominant mechanism. But If it isn’t, it would mean that the gradient of gravity is responsible. We don’t think it would be that tough to model….maybe a project for next week!
I was wondering if the centrifugal force created in the Earth-Moon rotation system would not be a better explanation for the bulge created on the opposite side?
the centrigugal force created by the 2 body (earth-moon) is indeed a factor, but if you calculate it, it is 10 times smaller resulting in a maximum of 30 cm on the axis. So it does contribute but is not the main component.
So are the tides dependent on the fact that the moon orbits the earth? If the moon where to suddenly be in geosynchronous orbit, would we then only experience a consistent high tide on the same side of the planet, as the water that needed to "catch up" would effectively eventually catch up to the rest of the water being pulled by the moon?
We would say the tides are dependent on the gravitational fields that nearby massive bodies create (the moon, sun, etc..) and that the two bulges should occur regardless of the specific type of orbit. If a planet is accelerating through another massive body’s gravitational field, it will experience tidal forces.
@@Waterlust But that's what I mean... if the moon stopped orbiting the earth and stayed in the exact spot relative to the earth, the earth is no longer accelerating through the moon's gravitational field.. it is just sitting in it.. Would we still have the tides (ignoring the sun's impact, etc)? Perhaps I misunderstood this all...
@@paulslund1 Understanding your question a bit more now.... If the Earth were in synchronous orbit with respect to the moon, then the same locations on Earth would always be facing the moon, and the tidal bulges the Moon’s gravitational field creates would stay in the same place. This would result in permanently high tides and low tides that wouldn’t change in time. Interestingly, this already is happening on the moon! The moon is in synchronous orbit with respect to the Earth, so the same side of the moon always faces the earth. This causes the tidal bulges on the moon to be permanently oriented, with the side facing Earth and facing away from Earth being slightly bulged out.
@@Waterlust Thank you again! So I guess I was pretty close with my assumption.. I thought that in the case of a permanent high tide/low tide scenario, that the high tide would only be on the side facing the moon, and the low tide on the opposite side (as that water "caught up" with the rest of the water.. but your description of the bulges on both sides of the moon indicates this isn't so....
@@paulslund1 yes, because it’s still in a constant state of acceleration, the two bulges would remain. The bulges would only go away if the Earth stopped accelerating towards the moon. Great question!
The claim is nonsense. The sublunar bulge is from gravitation pull of the moon but the antilunar bulge is from centrifugal force. This is because Earth & Moon rotate around a common centre of gravity inside the Earth but on the lunar side. Likewise with the Sun. Gravity pulls the sub-Solar bulge but centrifugal force creates the anti-Solar bulge since that part of the Earth is further from the Sun.
For example at 3:06, the force vector for the Moon is of different length than that for the Earth. This implies that the forces are not equal, which is not true.
I think what irks me about this incorrect treatment of tides is that it undoes the good work we try to accomplish in introductory physics courses. We emphasise the correct application of Newton's laws of motion. First we tell the students to identify the body in question, the body to which we will apply Newton's law. Newton’s first law tells us that an object will continue to move on a straight line at a constant speed, unless it’s acted on by an external force. And then it will continue to accelerate in the said direction and not stop. This video is NOT how the tides REALLY work?
@SebastianBode frame of reference is what is missing. The earth is rotating on its axis while orbiting the sun which is orbiting the galactic center. As the earth travels around the sun, the surface water is accelerated east and then west. Water has less mass than rock so it gets accelerated into a higher orbit/radius from the Earth's center. Newton's Laws of Motion accurately describes the Earth's tides. Add in Kepler's laws of motion, the closer to the sun, the greater the acceleration, and you have the king tide occurring the first of the year as the planet makes it closet approach to the sun. But it's on the back side of the planet as this is where the greatest amount of acceleration is taking place. Galileo theorized that the tides are caused by the earth's motion in space. GRACE mapped the Earth's wobble and attributed it to redistributed of ground water along the 45 degree latitude. This is where the most acceleration takes place and would have the most impact on the earths rotation. Gravitational attraction has been disproven. Only diehard relativists are still preaching it because it invalidates their beliefs.
Very interesting! I got a bit lost with the mathematics stuff but the idea of water getting left behind helped. Well presented and produced video. Thank you
The first sentence, about the tide moving up and down "every day" gives me pause. Since the very first sentence in the presentation is wildly inaccurate (the tide cycle happens TWICE per day) I am super hesitant to watch the rest. How much more misinformation will there be?
@oortcloud8078 Planets do not have gravitational attraction. Planets do not orbit a barycentre. The planet is rotating on its axis as it orbits the sun in am elliptical pattern. The tides are easily explained using Newton's Laws of Motion. What you call gravity is a Reactionary force. The resistance of the mass to being accelerated by an external force. The moon has no influence on the earth other than reflected light. The Earth's magnetosphere barely extends to the moon when its on the backside of the sun. Take away the sun and the moon and the Earth's orbit would remain unchanged. The Earth's orbit comes from the primordial cloud that formed the solar system. This gravitational attraction nonsense is a distraction from the real fundamental force of nature- Acceleration. F=ma or a=a. Acceleration equals Acceleration. Newton was confronted with the problem of explaining where Acceleration comes from. Two choices. A creator god or an eternal universe. As Carl Sagan would say. Both options are equally frightening to a scientist. That's why the entire scientific community is outright lying to you about gravity being mass attraction.
Does the resonance effect on the uniquely shaped Bay of Fundy mean that with rising sea levels, these highest tides will exponentially increase rather than just raise comparably with the actual water level increase?
That's an excellent question, and we're not sure of the answer. It would not surprise us if the resonance effect in the Bay of Fundy (also called a "seiche") responded non-linearly to sea level rise. We suspect this is, or will be, an area of active scientific research. Especially since critical infrastructure in that part of the world is not far from today's high water position.
What would happen if we dropped the moon on earth from 10m? It seems to me that small masses are unable to cause the earth to move significantly. It would seem when dropping a mass that is approximately 0% of the total mass, that only a single object needs to be thought as moving. And we are always dropping multiple objects that are approximately 0% of the total mass and they appear to land at the same time. But again what happens if we dropped something that had 30% of earths mass? Or what would happen if we instead dropped a ball and feather onto a ball of equal mass as the 1st ball? It would also seem to depend on how you dropped the objects as if all three are in free fall they would fall to a center of mass common to the 3 masses. I would think the 2 bodies with the highest energy would collide first. It just seems that we can say the mass of what is falling is not important when a single mass dominates all other objects. It would seem we would need to drop small objects from a much further distance to notice a slight amount of difference in “drop” times.
@@cybermonkeys sorry this question was not about tides. I got to the part of the video where they talking about gravitational acceleration. And acceleration only being dependent on a single mass. I would think the acceleration would be dependent on the total mass or total energy. Thank you for the information though. It seems to me that when we drop objects near earth to observe the effects of gravity we are in a unique scenario where a single mass dominates. I am just curious what would happen in a vacuum outside of the earths gravitational field if we dropped objects where a single mass did not dominate.
@@cybermonkeys thanks I will look into that. I did not make it past this part of the video because I was annoyed with this simplification. I do enjoy me some Dr. Becky so I will look for that video. Thanks for the response, Have a wonderful day as well.
@@cybermonkeys I just find that sometimes when things are simplified detail that was not important in the original situation is ignored. But it is not always insignificant in all situations. I want to know the conditions where it can be ignored and potentially where it cannot and why. Without understanding the fine detail one is limited to applying what has been learned into identical situations only. I prefer to learn the detail so I can adapt what I have learned to a wider variety of conditions. Again thanks for the insight and direction. The other videos were good.
A rather poor explanation of the tide on the opposite side to the moon. Both Earth and Moon rotate about the barycentre of the Earth-Moon system. This point is not at the centre of the Earth, rather nearer to the side facing the Moon, about 4700 km from the centre of the Earth. The far side of the earth is then rotating around the barycentre, which explains the lower tides on that side.
I thought that the primary tides were caused by the earth rotating around the centre of mass of the Earth - Moon system, the center of mass being about 1/3 of the earths radius in from the surface - on the same side that the moon is at any time. Then we have water being flung from the earth and attrated to the moon on one side, and water being "flung out" on the side opposite to the moon creating out diurnal tides. Then the sun has a similar but smaller effect, these two interactions then "beating" to give the neep and spring tidal variations in tidal heights. Oh and apparently Jupiter has around a 1% effect on our tides. ua-cam.com/video/Mr89IgzsMVk/v-deo.html
This is a wonderful piece of work. It makes a relatively complex thing easier to understand, without dumbing it down. Excellent eductation going on here.
This is a wonderful piece of shit. Excellent eductation for sheep.
I was a commercial fisherman. Maine USA. TIDE IS 10 feet. Florida is 1 foot. LOL. There is no bulge. The earth is flat.
@jiphy did you ever fall off the edge and hit your head?
Oh it is dumb as hell what this show spews. Open your eyes we are stationary.
For millions of years we chase a sun going 500k miles per our as we go around it at 66k miles per hour and spin at 1,000 mph at the equator.
We still see the same constellations with no parallax.
In winter say we are at 3 o'clock and in summer we are at 9 o'clock, right window left window yet the same view. Bullshit
Can't work
There is no tide on Earth
Tides are long waves across the oceans. They are caused by the gravitational force exerted on the earth by the moon and to a lesser extent by the sun. Wiki.
In fact, tides are an artifact of the up and down movement of coastlines in a stable ocean, caused by thermal expansion of the earth's crust due to sunlight moving westward.
Some coasts have no tides, some have only one tide, some have two tides, and some have four tides per day. Tides vary in height from 0 feet to 50 feet and move at different speeds and in different directions.
It is impossible for the moon's gravity to cause tides. Do you agree?
I'm 67 and no one has ever been able to satisfactorily explain tides to me...until now!!! THANKYOU!
Our pleasure! So glad it was helpful
@@Waterlust ua-cam.com/video/pwChk4S99i4/v-deo.html
too old to be told
@@huzaifabinraghibkhan5147 UMM-
Help?😭🙏
The music is very distracting and loud on headphones. Only saying this because otherwise this is a fantastic explanation! The animations make it so intuitive, appreciate all the work and I hope you make more. Thank you!
Exactly!!¡
agree
Great. Now I can’t ignore it.
It was perfect for me at every volume his voice was just louder
It's okay, but inadequate , because it does not mention the hundreds of tidal nodes around the world, where there are NO tides at all.
Science teacher and long term sailor here saying Thank you. What a great explanation. It cleared up a few points I couldn't quite get. Excellent education.
The very best explanation that I have seen. I understand the science and I watch certain vids to discover who does not, or cannot explain the science. You clearly know, and you can explain.
Just for future reference: the Bay of Fundy, with its funky resonance, has a counterexample. The Gulf of Thailand experiences one teeny tide per day. Very weird if you're planning your diving or navigation.
Whoa, we didn't know that. Will check it out. Thanks for sharing
This is the first time I've actually understood the tidal mechanism.
The bit about the water being "left behind" was key.
Well explained!
Thank you! We find that to be an "ah ha" moment as well. Glad you found it helpful. More ocean science videos like this to come, stay tuned.
@@Waterlustsurely, in order for the water to be "left behind", then the earth would have to accelerate quite quickly TOWARD THE MOON.
How can that be possible if the earth gravity is "six times stronger" than the moon's?
@@waynemoore8615 the rate doesn’t matter as much as the difference in rates. The difference in accelerations between Earth’s core and the fluid on its surface is very small, but because water can flow so easily and the ocean’s are connected, that small difference can produce noticeable changes in sea level.
⚖🗿The balance point of the rotating system is inside the Earth, not it´s center but shifted to the Moon.
So I would say centrifugal force causes the left behind bulge. 🪐🌀🌛Atmosphere should be affected a bit, too.
@@Waterlust If you are suggesting that the moon "pulls" the earth towards it with enough force (and suddenly enough) to leave some water behind it (slightly), then the mass of the moon and earth would have had to move closer together (slightly).
That would inevitably mean that:
1. The gravitational pull on each other would immediately increase, and
2. With no other force to stop that movement (newton's law), they would continue to accelerate exponentially, and collide after a small period of time.
Absolutely fantastic video, thank you. The best example of tides out there no question. Even famous "science communicators" have used the 2 bulge explanation. The only thing is - the background music is not background at all. Its way too loud. When the music pauses for a few secs just after 6:34 the video feels calmer and your voice is not overshadowed by the music. The music is okay - but needs to be much much lower volume so its barely even there. Thanks for a great vid!
That's the first time I've seen the "four little planets" explanation, or the ellipse-forming simulation. Very cool, very clear, and much more satisfying than the "traditional" explanations. Well done!
The four planets model was our "aha moment", glad you found it helpful!
I agree. I learned this from PBS Spacetime. Their visualization was of the whole earth with connected oceans. Showing it with the tiny planets, or particles, you are clearly able to see why the elongation happens on both sides of Earth. It also makes it easier to explain to someone else.
😂😂😂 wrong explanation
Syx 14:00
Waterlust crushed it! One of the best videos Ixve ever seen, in any subject. Not too long, not too short. Very well done. Take a victory lap!
Thanks so much, we try to find the right balance. Always a challenge!
Music is a bit loud and distracting, but great and informative video!
*_Uninformative Vídeo_*_ would be better, don’t you think?_
Someone told every youtuber you need music with your talking. I also find it distracting.
Sometimes, less is more
Hopefully he will reload this, without the noise, and speak slower.
@@andyphillips7435whiney ass
oh boy! several misconceptions cleared up here. now I know why friends have hesitated to fully explain the tide charts and graphs to me. thank you for doing the work!!!
I thought the opposite side bulge was created because the moon and earth system rotate around a point that is located between the earth and moon, creating the 2 bulges. Isn't this true also to some extent?
A science book I read gave the most basic simple explanation I have heard.
It said the moon pulls the water towards it on the near side, and pulls the earth away from the water on the opposite side.
It said thats why the tides have a higher and lower high tide each day.
Made a lot of sense to me.
@@wavydaveyparker , I never said it was correct. I simply pointed out that a book on science gave an alternate explanation that was very easy to understand and made sense, because two bodies exert gravitational forces on each other.
It also explained the two high tides we have each day with one being a "higher" high tide versus the other.
It also highlights an issue with inaccurate science information being published, and not just in this book.
Here's an example: It is impossible for gravity to create a star by the current model of a collapsing nebula of hydrogen gas.
Gravity simply can't pull the gas anywhere near tightly enough to form a star. The heat would easily overcome gravity as cause the gas to stay dissipated. Ever opened a tank valve at 3,000 psi, and seen the incredible force that the gas has, as it escapes?
Charles Law precludes star formation from happening by gravitational collapse.
The gravitational force causing collapse can't get anywhere near the level necessary to complete the process. Eventually the heat would easily overcome gravity.
And yet, we still see this being taught as how stars are formed.
Then we have the issue of planet formation. That doesn't pass muster either, but I won't go into that.
My point is, even accepted science being taught at the highest levels, in books other than the one I mentioned are not always accurate, and yet, it is still being taught.
Looks like they teach from comic books as well.
I'm curious how you might explain star formation?
(Academics are aware of these issues, but continue to teach them, and we blindly accept them as fact.
Then, to make it worse, a "rescue device" is tossed out there, rather than simply scratch our heads, and say, "We honestly don't know".
One such rescue device is this: An exploding supernova caused gravitational waves that compacted the gas tightly enough to allow gravity to take over. A child could see through all the holes in that.)
@@wavydaveyparker ,
NATIONAL GEOGRAPHIC had this to say about how tides form.
***I AM NOT SAYING IT'S CORRECT; ONLY THAT THE INFORMATION IS OUT THERE***
"The tidal force exerted by the moon is strongest on the side of the Earth facing the moon. It is weakest on the side of the Earth facing the opposite direction. These differences in gravitational force allow the ocean to bulge outward in two places at the same time. One bulge occurs on the side of the Earth facing the moon. This is the moon’s direct tidal force pulling the ocean toward it. The other bulge occurs on the opposite side of the Earth. Here, the ocean bulges in the opposite direction of the moon, not toward it. The bulge may be understood as the moon’s tidal force pulling the planet (not the ocean) toward it."
education.nationalgeographic.org/resource/cause-effect-tides/
The ocean on the opposite side of the Earth, opposite the Moon, wants to travel in a straight line, until acted on by an outside force.
That force is the Moon, so the ocean is pulled towards the Moon and travels in a circle instead of a straight line.
Because the Moon's forces are "tidal", they are different at different distances from the Moon. Therefore, the Earth is stretched into an ovaled ball, like gnocchi. That's a roundish pasta.
When orbiting a black hole, you are spaghettified. Stretched out into such a long line your molecules are disassembled.
Not a single part of you is pushed away from the black hole.
Same thing with the Earth Moon system. Not a single part is pushed away. All parts are pulled towards each other.
"Isn't this true also to some extent?"
No. Tidal forces can be explained _solely_ by gravity, no inertial "forces" required*. The video is correct (as is e.g. the one PBS Spacetime made 8+ years ago). While more complicated than the arguably more intuitive "centrifugal force does it" "explanation" it _does_ have the advantage of being, y'know, right :). Anyone believing otherwise has fallen victim to one of the most widespread myths about the tides (it's even offered as the explanation in a few textbooks - though others offer the correct explanation - as well as _many_ UA-cam videos etc. so it's a completely understandable mistake but it _is_ still a mistake).
If you really want to understand it though i'd suggest you don't take the word of people in UA-cam comments sections (that obviously includes me :) but instead google something like "tide physics myths" and look through the results, where you'll find plenty of articles from various authors, some aimed at lay readers, others published in peer reviewed scientific journals (with all the grisly/interesting - depending on your preference :) - mathematical details), correcting the various tide misconceptions. As one example, Prof. Donald Simanek created an excellent webpage years ago, which you can still find online, that in relatively simple terms explains _lots_ of misconceptions about physics (his article on tides specifically is called "Tidal Misconceptions").
(though - unfortunately in some ways - if you really, _really_ want to understand then, as with most things in physics, you kinda need to understand the mathematics. If/when you do you see that the equation for tidal force simply doesn't include terms for inertial "forces" and can be derived _solely_ from Newton's law of universal gravitation)
* OK _strictly_ speaking, in the framework of General Relativity gravity _itself_ is an inertial "force" but while true that's _also_ irrelevant in this context because here we're using the Newtonian framework, in which gravity is a real physical force (note the lack of quotes)
A a yacht Captain who has studied tides for decades, this is the best simple explanation particularly covering geographical anomalies. I will be sure to show this to many who ask about tides in my industry. Thanks.
That was SO WELL done!!! A wealth of information in a beautifully illustrative short video. So many questions that I've had about tides became clear in a matter of moments.
Right on! That was the goal. Glad you enjoyed it. More marine science videos like this coming, stay tuned!
I've known intellectually why tidal bulge occurs on both sides of the earth simultaneously - but never intuitively. Until now. Learning tickles, even at my age (75). Thank you!
@@oortcloud8078 Somewhere within this wretched hovel I call home is an ancient diploma granting me a Baccalaureate degree in physics. My particular interest was in orbital mechanics, so I'm already familiar with the barycentric nature of the earth-moon system. But it's been a long time, and knowing how something works isn't quite the same as knowing why. Still, I appreciate your taking the time to acknowledge this old fart's comment & sharing your own insights into the subject. All the best to you.
@@oortcloud8078 Well, I'm more like a Nutcase living in a genius of a Universe - but thanks. On one thing we do agree: You're never too old to learn.
Without doubt the best basic explanation for sea tides I've ever seen. Kudos! (and my commiserations for the tidal bores in the comments ...)
Stoked you found it helpful! And appreciate the support 🤣
Literally me when my dad calls me: 💀
Fun fact: while mass is measured in kg in scientific units, weight is a force and is measured in newtons, named after that guy who watch an apple fall. There are just under ten newtons in the force exerted on a one kg mass (the exact number is equal too the acceleration of gravity).
That means that an apple typically weighs around one newton. Nice!
That's cool!
@@wavydaveyparker almost... if you take into account microtides within any orbiting platform then the strictly weightless result only apple-ies of the centre of mass of the fruit lies on a two dimensional curved surface passing through the centre of gravity of the spacecraft.
I agree totally that anywhere in board it's going to be a long way short of the one newton I claimed.
thankyou Dr.Patrick Rynne and team Waterlust
@@cybermonkeys how they work?
@@cybermonkeysgot to know new dimesnsion from you. Thankyou sir
@@cybermonkeys sure
One of the best science videos on UA-cam. Informative, beautiful and entertaining!
Stoked you liked it! More marine science videos like this coming so stay tuned!
Best explanation I've heard ... will share this with many. I look forward to watching some of your other videos ... cheers
Very good video, helped me understand why there is 2 bulge of high tides. I can finally stitch together things.
Previously, I found out that gravitational force on Earth by the Sun is actually larger than the Moon, then I got confused as to why the Moon affects our tides more than Sun. Upon googling, I found out that it is due to the gravitational change gradient of Moon is larger. I had to satisfy myself to that answer until now, when I can finally stitch the concepts together with the help of your animation and explanation.
Thank you, from a high school physics teacher
Thank you for this complete explanation of all the tides. Both lunar and solar. I realize their are more but knowing just those and how they interact satisfies my curiosity.
So glad you enjoyed it! Most of the significant tides on Earth can be explained with just the moon and sun, so you've got the important ones covered!
Wow, I finally get tides! Insane how other videos and explanations in my textbooks growing up skipped all this. Thanks a bunch!!
Nailed it - best explanation of ocean tides I have ever heard.
hellz ya! Thanks Blake
Best explanation ever regarding the tides. Thank you.
Right on! Glad you found it helpful
Why the music!!!
This happens to be the best video to deal these topics . Brief & intriguing indeed.
I hope to find another video to discuss various alignments in details.
What a wonderfully clear, interesting explanation of tides. I, too, was taught the over-simplified version of how the sun and moon cause the earth to bulge, but never why the OPPOSITE also bulges...only that it does. If they just would have mentioned Newton's discovery to us, it would have been easy to figure that out, and, I would have understood why the moons of gas giants have a hard time surviving. Now I understand! Thank you for that knowledge!!!
What a wonderfully clear and interesting comment. Yes, Newton firmly established that a common centre of gravity was a prerequisite for all celestial bodies in motion. This wobbly inertial movement is definitely the main cause behind the tides, although it still required the insights of Laplace to complete the picture. Thanks
Gteat content! There is more. The moon varies in its orbit from north to south snd back again which gives us the difference between tide extents - meaning the high tide is higher than the next high tide, and the low tide is lower than the next low tide when the moon is not orbiting at our equator, but is rather orbiting north, or south of it. If you’re a surfer, this is very interesting and useful.
What's amazing is that something as ancient, familiar and well-studied as the tides, still have more that can be learned about them.
I think this video came up in my feed because i have been researching the size of ancient tides going back to when the moon originally formed. I saw a post on Quora complete with math that suggested ancient tides were over a kilometer high. Since its formation, the moon has been slowly spiralling outward from the Earth and slowing its primary's rotation in the process. Not only did Earth have tsunamis of water sloshing around every few hours but likely also tides of lava oozing from the partially cooled and tortured crust. Would love to see a video about Ancient Tides of the Early Earth. We look at the moon as a beautiful and peaceful symbol of serenity but in the early years of the planet, it was more like a blender. A blender powered by a chainsaw.
This is a fascinating subject!
In an above comment I did a quick calculation and estimated the Roche limit is about 15,000 miles, which is where the Moon formed. Perhaps 16,000 miles.
So, that's 4 times the Earth's radius, so orbital period would be 4 to the 3/2 power, which is 4 times 1.414, which is about 5.6 times greater than the ISS's 1.5 hour orbit, so about 8.5 hours.
Oh, crud. The Earth was rotating about once every 4 hours. Shoot. Well, I guess the tidal "wave" would come by about twice every 4 hours.
Dang, that's fast! At the equator, that's 25,000 miles per 2 hours, about 12,500 miles per bour.!
Best Tide explainer I’ve ever seen, and I’ve been interested in this topic for decades.
This is the future of education. You need to start a home school curriculum with these types of videos. Great job!
As a kid I'm the 1960's the tides were a huge part of my life, even in winter, we lived right on the coast of the northeast Atlantic, those deep green waters are in my blood.
Great work, I'm a kayak instructor and the over-simplified "two bulges" diagram is such a massive sticking point when teaching tide theory. Thanks for going the extra mile, will definitely be sharing this with students.
Glad you found it helpful. More marine science videos like this coming, stay tuned!
I wish you wouldn’t Mr Waters, because this isn’t how the tidal waters work. Please stick with Newton’s Equilibrium Theory first, and then move onto the Dynamic Theory, which was discovered by Euler and Laplace.
This has been the best video about tides i've seen so far. However, it still sticks to the idea of two (or more) bulges circling our planet in pretty much one day.
This is outstanding! Would love to see more of these! I learned a lot!
Thanks so much. More coming! Stay tuned
@@Waterlust EINSTEIN IS UNCOVERED AND OUTSMARTED BY FRANK MARTIN DIMEGLIO:
WHAT IS E=MC2 is dimensionally consistent, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. Indeed, consider what is the man (AND THE EYE ON BALANCE) who IS standing on what is THE EARTH/ground; AS touch AND feeling BLEND; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE). Indeed, WHAT IS GRAVITY is, ON BALANCE, an INTERACTION that cannot be shielded or blocked. GREAT. BALANCE AND completeness go hand in hand, AS it all CLEARLY makes perfect sense ON BALANCE. Magnificent.
By Frank Martin DiMeglio
The sun's tide-generating force is about half that of the moon. One half times one third is one sixth. Consider what is water. The density of what is the Sun is believed to be about one quarter of that of what is THE EARTH. The diameter of WHAT IS THE MOON is about one quarter of that of what is THE EARTH. The density of the human body is about the same as water. Lava is about three times as dense as water. Pure water is about half as dense as packed sand/wet packed sand. We can multiply one fourth times two thirds in order to ALSO get the surface gravity on the Moon in comparison with what is THE EARTH/ground. The gravity of the Sun upon the Moon is about TWICE that of what is THE EARTH. The lunar crust is about TWICE as thick on the far side of what is the Moon. Notice what is the TRANSLUCENT AND BLUE sky ON BALANCE. The maria (lunar “seas”) do occupy ONE THIRD of the visible near side of what is the Moon. One half times one third is one sixth. What is E=MC2 is taken directly from F=ma, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. Consider what is the orange AND setting Sun ON BALANCE. Consider what is THE EYE ON BALANCE. Consider what is the fully illuminated AND setting/WHITE MOON ON BALANCE !!! What is E=MC2 is dimensionally consistent. The land surface area of what is THE EARTH is 29 percent. This is EXACTLY between (ON BALANCE) what is one third AND what is one fourth. The maria occupy one sixth of what is the Moon. The BULK DENSITY of what is the Moon is comparable to that of (volcanic) basaltic lavas on what is THE EARTH/ground. Consider what are the tides. ONE HALF times one third is one sixth. ONE QUARTER times two thirds is one sixth. What is gravity is, ON BALANCE, an INTERACTION that cannot be shielded or blocked. CLEAR water comes from what is THE EYE (ON BALANCE). ON BALANCE, what is THE EARTH is ALSO BLUE !!! GREAT. BALANCE AND completeness go hand in hand. What is LAVA IS ORANGE, AND it is even blood red. Awesome. Yellow is the hottest color of lava. Blue is the hottest flame color. Note: Consider what is the blue flame. The lunar surface is chiefly composed of pumice. Volcanic ash is present as well. The topologic range (lowest to highest spots) on what is the Moon IS about THE SAME as that of THE EARTH (i.e., about 15 kilometers). This is the approximate distance from the very bottom of the Marianas trench to the top of the Himalayan mountains. Magnificent. The bottom line: What is gravity goes way beyond what Einstein tried to lay claim to (and to descriptively isolate). That is abundantly CLEAR. He never nearly understood what is TIME.
By Frank Martin DiMeglio
In understanding SPACE, what is gravity, TIME, AND time dilation (ON BALANCE), it is important is it to understand what is a BALANCED displacement of what is SPACE. ELECTROMAGNETISM/energy is gravity ON/IN BALANCE.
Consider what is E=MC2. TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE. Consider TIME AND time dilation ON BALANCE. (c squared CLEARLY represents a dimension of SPACE ON BALANCE.) Indeed, the stars are POINTS in the night sky ON BALANCE. The rotation of WHAT IS THE MOON matches the revolution. Consider what is THE EYE, AND notice what is the TRANSLUCENT AND BLUE sky ON BALANCE. NOW, consider what is the BALANCED MIDDLE DISTANCE in/of SPACE. CLEARLY, BALANCED inertia/INERTIAL RESISTANCE is fundamental (ON BALANCE). “Mass"/ENERGY IS GRAVITY. ON BALANCE, consider what is the orange (AND setting) Sun. “Mass"/ENERGY involves BALANCED inertia/INERTIAL RESISTANCE consistent WITH/as what is BALANCED electromagnetic/gravitational force/ENERGY, AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS gravity/acceleration involves BALANCED inertia/INERTIAL RESISTANCE (ON BALANCE) consistent WITH E=MC2, F=ma, TIME, AND time dilation ON BALANCE. This CLEARLY AND NECESSARILY represents, DESCRIBES, AND INVOLVES what is possible/potential AND actual ON/IN BALANCE, AS ELECTROMAGNETISM/energy is CLEARLY (AND NECESSARILY) proven to be gravity (ON/IN BALANCE). Notice what is the fully illuminated (AND setting/WHITE) MOON ON BALANCE. Great. TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE. Indeed, inertia/INERTIAL RESISTANCE is proportional to (or BALANCED with/AS) GRAVITATIONAL force/ENERGY; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE). This CLEARLY explains what is E=MC2 AND F=ma ON BALANCE, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE !! (Consider TIME AND time dilation ON BALANCE.) Great. Indeed, consider WHAT IS THE EARTH/ground ON BALANCE. I have mathematically proven why the rotation of WHAT IS THE MOON matches the revolution, AS ELECTROMAGNETISM/energy is CLEARLY (AND NECESSARILY) proven to be gravity (ON/IN BALANCE). Consider TIME AND time dilation ON BALANCE, AS the stars AND PLANETS are POINTS in the night sky ON BALANCE; AS c squared CLEARLY represents a dimension of SPACE ON BALANCE. (Consider what is THE EYE ON BALANCE.) I have mathematically proven what is the fourth dimension, AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE) !!! I have explained why what are OBJECTS may fall at the SAME RATE.
By Frank Martin DiMeglio
Finally, an easy to understand explanation
Great Job, complete, clear and concise at the same time. Thank you !!
With high school education, that was a beautiful explanation,thank you dearly.
Glad you enjoyed it! More videos like this coming soon about other cool ocean science topics
5:16 decompose the vectors from the upper and lower planet. You get arrows pointing perpendicular to the poles of the planet. This pushes water out to the sides. Why wasnt this included here? Also, the COG from the moon/earth system is on the moons side of the earth, making the ‘’polar force push’’ greater on one side.
i agree
On fact you have left out is the drag or lag factor. Spring tide low is always at about 9am in the morning where I am. If you look at your illustrations of the bulge this should be at 6am when the sun and moon is rising but it takes place about 3hrs later.
Great point!
Excellent presentation! As a coastal engineer I’m familiar with tidal constituents and where they come from, but this is an unusually lucid explanation of this complex phenomenon which, as you said, many textbooks still get wrong. Next video, maybe you can tackle why referring to tsunamis as “tidal waves” is just wrong!
Right on! We call out the tsunami/tidal wave confusion in our video about tidal bores! ua-cam.com/video/F-EoL4Jf7ug/v-deo.html
Thank you so much, excellent video.
finally a logical and simple explanation that matches actual observation of the tides, the popular explanations never sat ok with me because they never did.
Great video! One minor comment. The time for a shallow water wave to traverse the Bay of Fundy (and back) is much less than 12.42 hours. The resonance is with the entire Gulf of Maine.
Great point!
The River Severn in England has a wide tidal range - 2nd only to Fundy it is claimed. This results in a tidal "Severn Bore", which I think is caused by the estuary getting narrower and shallower, so as a wave approaches from the ocean the deeper water slows down & the surface water overtops it.
Thank you for this ponderously luminous eye-opener.
While a good explanation of the "tidal forces" between objects, they are not strong enough to cause ocean tides. You have to account for centrifugal forces on Moon and Earth orbiting their center of mass. See Richard Feynman, Lectures on Physics, section 7-4.
You are entirely incorrect. Centrifugal forces are simply centripetal forces that are perceived in a different reference frame.
It's like putting a camera on Newton's apple and dropping it. Is the Earth accelerating toward the apple? No. But centrifugal forces would say such a thing because of the incorrect reference frame.
@@MultiPleaserthe earth is accelerating towards the Apple in an infinitesimally small way though. That’s how gravity works. Objects are attracted to one another based on their mass. While the earth exerts a force on the Apple and it accelerates towards the ground (center of the earths mass), the earth in turn is accelerating towards the the surface of the apple (center of its mass).
@@MultiPleasersurely an apple dropping to earth would be a linear force.
Why are you saying its is a centrifugal force?
@@waynemoore8615 I did not. I said it's LIKE the Earth being drawn to the apple b/c of the different reference frame.
@@chrismiller5882 You're missing the point.
Dear Dr Rynne, I understand that the Earth Moon system rotates about the barycentre which is 1/3 the way below the Earth's surface. The 2nd bulge in tides is the centrifugal effect of this rotation. The Earth's orbit is traced out by the barycentre.
That’s a question others have posed here in the comments section and we’re working on a follow-up video to get into the finer details 👍🏼
@@WaterlustWhat does the barycentre have to do with the tides? Sounds like more flat earth nonsense.
I suggest you research Nicholas Tesla and see whst he had to say about Einstein’s Relativity nonsense.
2) Galileo's ball drop experiment and his theory that the tides are the result of the Earth's MOTION in space and not it's mass.
3) the many followup experiments to Galileo's ball drop tests. The hammer&feather on the moon. The bowling ball and feather in Nasa's vacuum chamber.
4) the LIGO project. The detectors were PUSHED out of alignment. Not pulled.
5) Newton's Laws of Motion. F=ma. Force comes from Acceleration of the mass. Not the mass itself. 3rd law of motion, Action and Reaction. Gravity/g-force is a Reactionary force. The resistance of the mass to being Accelerated.
6) Kepler's Laws of Motion. In an elliptical orbit, as the radius decreases, the acceleration increases. This results in the annual high tide on the side OPPOSITE the sum as this where the most acceleration is occurring.
The earth-> rotating on its axis creates a centrifugal force. Acceleration its mass outward and forward creating a tidal bulge as the water gets Accelerated to a higher radius/orbit. Add on the planets orbital frame and you get two tides per day as the mass is accelerated clockwise and then counterclockwise as the earth rotates in relation to its path around the sun.
Just remember, m=m. It's only attribute is how much space the object occupies. F=ma is what space it occupies. As the radius increases, so does the acceleration factor causing a decrease in mass. The atmosphere becomes thinner with altitude on account of an increase in acceleration with a constant force (Earth's axial rotation velocity).
Lovely graphics, but no mention of centrifugal effects on tides
Brilliantly explained
Very clear explanation, i love the part where you split the planet in 4, a very nice way to move toward a gravitational field notion. I will sure reuse it!
My understanding has always be that although the maximum of the gravitation field is just 'below' the moon (on the moon-earth axis, moon side) as you explain and draw, the inertia of a body of water makes it that the actual bulge is 'late', by an amount that from memory is close to 90° so that at the end, the bulge of water is about opposite to where it is classically drawn.
As it makes the explanation a bit more confusing, i tend to just add this notion after where your nice video brings us.
Super interesting, we hadn't heard about an offset between the tidal bulges and the earth-moon line caused by inertia/earth's rotation. We're not sure that actually happens, we will have to read up more on it! One point we'd bring up is that the concept of the tidal bulges is somewhat simplified since the planet isn't entirely covered in water (land affects things), and there are many "bulges" in different locations simultaneously. The classic example of the moon bulges is specific to the M2. One way we like to look at it, is that each "bulge" is a wave, and each wave is traveling around the planet. Sometimes multiple waves hit the same place at the same time (eg: spring tides), and the location of land masses can interrupt how fast the waves make their way around the planet. NOAA has a nice discussion about this at the link below...though they do suggest that if the earth were entirely covered in water, the bulges would align with the axis of the respective celestial bodies causing them. Though at the same time, just because NOAA says it, doesn't mean it's necessarily true... oceanservice.noaa.gov/facts/moon-tide.html
@@Waterlust I've not been able to find the book where i think i read the 'around 90° offset' (cause it was a borrowed paper one), only its reference so far. The wikipedia article hints at this offset by saying 'The moment of highest tide is not necessarily when the Moon is nearest to zenith or nadir' but is non commital on how much of an offset we could expect in general. The Bathymetry chapter (en.wikipedia.org/wiki/Tide#Bathymetry) gives an example of 2 and a half hour offset for Norfolk, Virginia, so more like 40° in this case.
I totally agree that the coastal effect have a lot more impact (including in delaying the tidal wave), but they are also a lot more difficult to explain in simple terms. M2 bulge is the first thing to explain, but i'm just worried that drawing it aligned with the bulge in the gravity field is giving a too simple but too inaccurate result.
The tidal bulge does preceed the Moon and accelerates it tangentially, which makes it move away from the Earth and slow down.
The tidal bulge also slows down the Earth's daily rotation, because the Moon is pulling back on the Earth as well.
From old memory, the Earth started out with about a 4 hour day and the Moon's orbit was about 6 hours. But, because the tidal bulge preceeds the Moon by a few degrees (definitely not 90, but more like the 30 mentioned in a reply) the Moon is accelerated just like when your hand moves in a circle ahead of the rock in your sling, as you accelerate a stone in order to slay Goliath.
The leather string becomes more taught and stretches as the stone speeds up and centripetal forces increase.
So, the Moon moves away from the Earth because as an orbiting object accelerates, it doesn't speed up, but rather increases in orbital radius, and slows down.
Right now the Moon is retreating from the Earth about 1.5 inches a year as I recall. It might be 2 cm, which is 4/5ths of an inch. Might want to check that. Anyways, it's about the speed of continental drift: slow.
The Moon is currently moving just over 2000 mph, maybe 2200. But it varies a lot thanks to the very elliptical orbit.
When the Moon first formed, and had a 6 hour orbit (just outside the Roche limit you talked about) it's velocity was a lot closer to the International Space Station's 17,500 mph.
Equations exist for determining the Roche limit, and as I recall they are typically a ratio of radii, adjusted for density. Since the Moon's density is half of the Earth's, and it's radius is 3.666 times less, then the Roche limit is... guessing around 15,000 miles. That's a lot closer than the current 239,000 mile average.
If my guess is correct, and orbital radius started out at 15,000 miles, then orbital period was about 5 times longer than the ISS, so about 7.5 hours.
Tides were insaely high and very fast, and probably eroded entire continents, if there were any after the crazy impact than formed the Moon.
Excellent job! As a lifetime sailor, your info hits home, particularly around the need to listen to locals to understand. I wish, however, you have mentioned one group of people who know the tides better than anyone else in a given region: indigenous peoples. Perhaps not the why of it, but certainly the what, when, and how of it.
The best explanation of tides I have seen so far on UA-cam.
I wish you had added some additional examples of where and how resonance results in high tides. For example Incheon, South Korea has 34 foot tides but the coastline does not seem to resemble the Bay of Fundy.
South Korea is a developed country, and as such it uses metric, so that would be a 10m tide, not 34 foot. There's only 3 undeveloped countries still using imperial units.
this is the best explanation about tides. thanks for sharing!
This is the best video, and first understandable explanation I have found so far. Kudos!
This is the best explanation on this ever
I had read a good explanation for tides before, but the video explained it beautifully and in more detail, particularly the tidal constituents and their relative timings.
This is why I pay an internet provider.
Also, seeing a totally unexpected glimpse (09:54) of my hometown in this video was a nice bonus.
This is a brilliant explanation!!
Awesome video! This is the BEST explanation of tides👍👍
Why this video has so little likes is beyond me. Great work.
the algorithm hasn't graced us with its attention yet
If you want more likes, turn down the background audio to a minimum of a third of the speakers volume. Sounds more like a music video instead of a very interesting and educational video. That's just my opinion but I have a feeling much of your viewing audience would agree
Beautiful thanks, I wish I could explain things with such elegance.
Thanks so much!
Great job for giving a 80% complete explanation for the marines tides, but as I'm picky, I'm missing the "jewel on top of the crow" which would make this video really outstanding: the explanation about amphidromic points and the influence of the Coriolis force on all this moving water! You did the same trick as those videos that present the two bulges and says "too complicated to explain".
sounds like we need to do a follow-up video! We always struggle with figuring out how much information is too much or too little. Thanks for the feedback!
@@Waterlustthanks for the great work you have done here in this video- just one request in your next video please keep the music down and your voice up so I can focus on the information better.
Thanks anyway.
@@sydanas7564 will do!
@@Waterlust There are times, when one has to 'fib', and leave out the real/extra information, so, as to convey the concept.
Add too much, and you could lose the audience, they either get confused or lose interest.
the view count analogy is incredible... perfectly described in the first minute.
exceptional essay. excellent work.
at 2:53 the statement "bigger objects create stronger gravitational forces than smaller ones" should have been worded "more massive objects.....less massive ones".
Good point
This is the best video on thie subject...I have seen many many videos on this, and none of those gave me a complete intuitive understanding of what goes on.
So glad it was helpful! More marine science content like this coming. Stay tuned!
I grew up in Anchorage Alaska and they have the 4th biggest tidal change in the world and are number 1 for cities in the United States. Anchorage sits on a peninsula in Cook Inlet with Turnagain Arm to the south and Knik Arm to the north. The tidal change between high and low tide averages just around 30 feet and going up to over 33 feet for Anchorage and Turnagain Arm. Surfers and paddle boarders regularly ride the bore tides that occur when the tide is coming back in. They can ride the bore tide for miles if they’re lucky. But when the tide is low Turnagain Arm becomes a mudflat with just the river channels flowing through it. The mud is sticky and nasty and snags unsuspecting people in when they unknowingly walk on the mud. The extreme tides makes Turnagain Arm unusable for boats really because of its shallow depths.
Such an amazing part of the world! We have a video about the physics of tidal bores too that you might enjoy
I remember learning about this when I traveled to Alaska in the summer of 2022 for a vacation. We were on a train and traveling next to some of those mud flats and a tour guide was talking about it.
OMG - I spent 4 years in Alaska as a young kid(Elmendorf AFB) and always thought it was pronounced Ptarmigan after the fowl! Crazy. I guess if I had paid more attention to my Alaskan History, I would have known better. Thanks.
Beautifully done.
What a fun, engaging, and educational video!! Awesome job team!
Awww thanks Jake!!
Seems to have made the topic unnecessarily complicated. I still don't know how the tides work despite spending a great amount of time at the seaside.
I live near the bay of Fundy! Hopewell rocks is amazing, you can literally walk on the sea floor.
The Bay Of Fundy is incredible! If you haven't already seen it, you'll like the video we made on Tidal Bores that includes surfing the bore in Moncton! ua-cam.com/video/F-EoL4Jf7ug/v-deo.html
Trying to listen - why is the background "music" so LOUD?
Good explanation. One minor complaint; the narration at 8:45 is misleading and seems to imply that the tidal forces vary as 1/r^2, when they actually vary as R/r^3, where, for the earth, r is the distance to the source of the tidal force and R is the distance from the center of the earth.
Yes, this a great point and something we may address in a follow-up video. It is the gradient of gravitational fields that controls the magnitude of the tide, so the first spatial derivative leads to the 1/r^3 dependence and explains why the moon is more influential despite the suns gravitational force being stronger on Earth. We missed an opportunity by not including that and wish we had.
I would give this a Two-Thumbs-Up. As said in other comments, it takes a complex subject and explains it so more of us laymen can understand it.
👍😉👍
Glad it was helpful! More marine science content like this coming. Stay tuned
😢😢😢 totally wrong explanation dear
Great perfect writing, explanations and models.
Very entertaining! However, why do you only consider the ‘tidal force’ in linear ‘free-fall’ motion? We get the exact same results when we experience a ‘tidal force’ in orbital ‘free-fall’ motion around a common centre of mass. And its certainly safer, more realistic and adheres to the accepted laws of Motion, which were laid out by that Newton guy you mentioned, and we wouldn’t have to contend with any messy unavoidable collisions? Which wouldn’t be very environmentally sound for any of us! Anyway, I enjoyed the presentation and congratulations. Take care.
We present the context of linear acceleration as it's far simpler to illustrate to a layperson. The stretching effect caused by gravitational fields is the same whether an object is accelerating through them linearly or centripetally.
@@Waterlust That’s interesting and thanks for bothering to reply, it’s much appreciated. Maybe it’s just me, but I distinctly got the impression from your beautifully animated introduction, that you wanted to get away from the usual, boring, monotone, layperson speak, where lesser competent content creators, unlike yourselves, usually say, “there is a bulge on the far side and don’t ask why? It’s just there???” I honestly think your superbly produced production deserved better…than to just say, the Earth accelerates towards the Moon leaving water behind. It’s just a shame, when you were so close to providing the correct answer for, “why tides really happen?”
The ‘squeezing’ effect on oceans - _and it’s not a ‘stretching’ effect, because water cannot be stretched_ - caused by gravitational fields is not the same whether an object is accelerating through them linearly or centripetally.
If it’s linearly, then the end result is destruction and we get rapidly increasing tides.
If it’s centripetally then, the earth and moon are in a balanced orbital motion around a barycentre and inertia has to be recognised, and then we can all gratefully, continue to correctly predict and experience our wonderful tidal systems every single day.
However, who am I to talk? … Just someone who was taught Physics correctly at school I guess, by an extremely good teacher - but who cares! Thanks for the chat.
@@wavydaveyparker Interesting stuff! We think there can be legitimate debate regarding which term, “squeeze” or “stretch” should be used…but the overall message is that the gradient in gravitational fields, and the motion it produces, produces deformation of celestial bodies, including the tides.
The idea of using the centrifugal “force” to justify the far side deformation is interesting and we’ve seen it widely used. Our problem with it is that it's a little misleading and in some cases insufficient. Centrifugal forces are “apparent forces”, they don’t explain why tidal force deformation happens in linear acceleration cases (as modeled in Matlab in the video), and why tidal force deformation is always symmetric, regardless of the celestial body or its orbit.
An explanation based solely on gravitational fields doesn’t seem to have these problems, while also preserving the physics of inertia and the apparent centrifugal forces of orbits. The idea that the planet accelerates away from water on the far side is equivalent to saying the water experiences a centrifugal force due to the orbit. It's just presenting it in a different way.
That’s at least our perspective on it….it’s a fascinating subject and we enjoy thought provoking discussing about it! Thanks for participating
@@Waterlust And I wholeheartedly agree, the Astronomical part of the discussion is a fascinating subject and I thank you for engaging in this thought provoking friendly chat. I certainly don’t want our conversation to detract from your otherwise excellent video, which I still think is very interesting and well made. And, at least you didn’t bring up the crazy idea of planets performing ridiculous start-stop motions and partial bulge filling, which I’m sure you’d agree is totally misleading. _I did make a daft little video about that if you’re interested? 😄 any kind support is always welcome!_ …
Anyway, here’s the thing! Your first sentence summed up the confusion most people face when thinking about gravity and orbits…
_“The overall message is that the gradient in gravitational fields, and the motion it produces, produces deformation of celestial bodies, including the tides.”_
The gradient in gravitational fields does produce deformation of celestial bodies in the form of tides. However, they have nothing to do with the actual motion of planets, that is the sole domain of inertia. The planets don’t move because of gravity, they move because they initially had inertia, and wish to continue in there straight line paths forever. It’s only when gravity gets involved that there motion is shaped, into what we perceive as orbits in a curved space.
Now, I don’t want to get into ‘apparent’ forces and reference frames here, because I’ve been over that a jizillion times!!…despite to say, that gravity itself can also be considered as a ‘fictitious’ force. So, instead I’ll finish with something you might like to consider if you decide to produce a possible follow up video, because this is where you came so agonisingly close to being right on point!
Stick with the concept of ‘free-fall’ … which you alluded to in your video. What Newton concluded and what Professor Brian Greene demonstrated in an excellent video on Relativity, was that when a celestial body is in orbit around a barycentre, it experiences a zero ‘net’ acceleration at its centre. The tidal force is caused from this point outwards. Tides are actually formed by the buildup of lateral, hydrostatic pressure in the oceans on either side…and, when I say, ‘side’ I mean near and far.
However, that just my considered opinion, based on the scientific evidence provided by my teachers, but what do they know! Nothing!! … That’s what?
Kind regards, wavy.
@@wavydaveyparker Interesting points, though the inertia mechanism wouldn't result in tidal bulges in linearly accelerating celestial bodies, it would only apply when there is an orbit. Though, do linearly accelerating celestial bodies have tidal bulges?…we’re not sure there are any documented cases of that. We also wonder how the bulges end up being symmetrical. The inertia argument only applies to the bulge on the far side, so what about the close side? The explanations we've seen say that the bulge on the close side is caused by gravitational attraction, while the far side is inertia, and yet somehow...they are both the same magnitude. We haven’t done the math, but that seems a little fishy.
One idea we had is to simulate a cluster of particles in the way we did in the video with Matlab. Instead of using the universal law of gravitation to calculate all the forces, we could create a virtual world where the gravitational force between objects is not distance dependent (in other words, the force of gravity = G*M1*M2). In that fake world, orbits could still be maintained, and we could model a cluster of particles orbiting another celestial body. If the cluster is deformed in the way we see in real life, it would support the idea that inertia is the dominant mechanism. But If it isn’t, it would mean that the gradient of gravity is responsible.
We don’t think it would be that tough to model….maybe a project for next week!
I was wondering if the centrifugal force created in the Earth-Moon rotation system would not be a better explanation for the bulge created on the opposite side?
the centrigugal force created by the 2 body (earth-moon) is indeed a factor, but if you calculate it, it is 10 times smaller resulting in a maximum of 30 cm on the axis. So it does contribute but is not the main component.
So are the tides dependent on the fact that the moon orbits the earth? If the moon where to suddenly be in geosynchronous orbit, would we then only experience a consistent high tide on the same side of the planet, as the water that needed to "catch up" would effectively eventually catch up to the rest of the water being pulled by the moon?
We would say the tides are dependent on the gravitational fields that nearby massive bodies create (the moon, sun, etc..) and that the two bulges should occur regardless of the specific type of orbit. If a planet is accelerating through another massive body’s gravitational field, it will experience tidal forces.
@@Waterlust But that's what I mean... if the moon stopped orbiting the earth and stayed in the exact spot relative to the earth, the earth is no longer accelerating through the moon's gravitational field.. it is just sitting in it.. Would we still have the tides (ignoring the sun's impact, etc)? Perhaps I misunderstood this all...
@@paulslund1 Understanding your question a bit more now.... If the Earth were in synchronous orbit with respect to the moon, then the same locations on Earth would always be facing the moon, and the tidal bulges the Moon’s gravitational field creates would stay in the same place. This would result in permanently high tides and low tides that wouldn’t change in time.
Interestingly, this already is happening on the moon! The moon is in synchronous orbit with respect to the Earth, so the same side of the moon always faces the earth. This causes the tidal bulges on the moon to be permanently oriented, with the side facing Earth and facing away from Earth being slightly bulged out.
@@Waterlust Thank you again! So I guess I was pretty close with my assumption.. I thought that in the case of a permanent high tide/low tide scenario, that the high tide would only be on the side facing the moon, and the low tide on the opposite side (as that water "caught up" with the rest of the water.. but your description of the bulges on both sides of the moon indicates this isn't so....
@@paulslund1 yes, because it’s still in a constant state of acceleration, the two bulges would remain. The bulges would only go away if the Earth stopped accelerating towards the moon. Great question!
Clearest explanation I have ever heard! 🙏🏽🙏🏽🙏🏽☀️☀️☀️
Seems background music is getting ubiquitous on UA-cam content. It's so distracting, can't finish the videos.
The vid i was looking for for 5 years!! Thank you❤
Idk. A course in GR might help you model this more accurately.
Thanks. I've been trying to answer why there are two high tides a day and not one for 25 years... Now I understand. Very clear explanation also.
Awesome! Glad it was helpful More ocean science videos like these coming, stay tuned!
The claim is nonsense. The sublunar bulge is from gravitation pull of the moon but the antilunar bulge is from centrifugal force. This is because Earth & Moon rotate around a common centre of gravity inside the Earth but on the lunar side.
Likewise with the Sun. Gravity pulls the sub-Solar bulge but centrifugal force creates the anti-Solar bulge since that part of the Earth is further from the Sun.
Impressively informative. Forgot to mention the phase delay of the time it takes the water to actually chase the moon.
lunitidal intraval time
Fantastic video. Thank you for making such educational content!
Our pleasure Susan! Our hope with these videos is to create material that is both entertaining and educational!
For example at 3:06, the force vector for the Moon is of different length than that for the Earth. This implies that the forces are not equal, which is not true.
I think what irks me about this incorrect treatment of tides is that it undoes the good work we try to accomplish in introductory physics courses. We emphasise the correct application of Newton's laws of motion. First we tell the students to identify the body in question, the body to which we will apply Newton's law. Newton’s first law tells us that an object will continue to move on a straight line at a constant speed, unless it’s acted on by an external force. And then it will continue to accelerate in the said direction and not stop. This video is NOT how the tides REALLY work?
What's missing in their explanation ?
@@SebastianBode Centrifugal force is what is missing in this explanation...
What the hell are you talking about. All those smarts and can't get your point across.
@SebastianBode frame of reference is what is missing. The earth is rotating on its axis while orbiting the sun which is orbiting the galactic center. As the earth travels around the sun, the surface water is accelerated east and then west. Water has less mass than rock so it gets accelerated into a higher orbit/radius from the Earth's center. Newton's Laws of Motion accurately describes the Earth's tides. Add in Kepler's laws of motion, the closer to the sun, the greater the acceleration, and you have the king tide occurring the first of the year as the planet makes it closet approach to the sun. But it's on the back side of the planet as this is where the greatest amount of acceleration is taking place.
Galileo theorized that the tides are caused by the earth's motion in space.
GRACE mapped the Earth's wobble and attributed it to redistributed of ground water along the 45 degree latitude. This is where the most acceleration takes place and would have the most impact on the earths rotation.
Gravitational attraction has been disproven. Only diehard relativists are still preaching it because it invalidates their beliefs.
That's your opinion of it ..
It's just mindblowing how this place was made.
I live in Montana. The only Tide I have ever seen is at the grocery store in the laundry detergent aisle. 😅
🤣
Very interesting! I got a bit lost with the mathematics stuff but the idea of water getting left behind helped. Well presented and produced video. Thank you
The first sentence, about the tide moving up and down "every day" gives me pause. Since the very first sentence in the presentation is wildly inaccurate (the tide cycle happens TWICE per day) I am super hesitant to watch the rest. How much more misinformation will there be?
@oortcloud8078 Planets do not have gravitational attraction. Planets do not orbit a barycentre.
The planet is rotating on its axis as it orbits the sun in am elliptical pattern.
The tides are easily explained using Newton's Laws of Motion.
What you call gravity is a Reactionary force. The resistance of the mass to being accelerated by an external force. The moon has no influence on the earth other than reflected light.
The Earth's magnetosphere barely extends to the moon when its on the backside of the sun.
Take away the sun and the moon and the Earth's orbit would remain unchanged. The Earth's orbit comes from the primordial cloud that formed the solar system.
This gravitational attraction nonsense is a distraction from the real fundamental force of nature- Acceleration.
F=ma or a=a. Acceleration equals Acceleration. Newton was confronted with the problem of explaining where Acceleration comes from. Two choices. A creator god or an eternal universe.
As Carl Sagan would say. Both options are equally frightening to a scientist.
That's why the entire scientific community is outright lying to you about gravity being mass attraction.
Does the resonance effect on the uniquely shaped Bay of Fundy mean that with rising sea levels, these highest tides will exponentially increase rather than just raise comparably with the actual water level increase?
That's an excellent question, and we're not sure of the answer. It would not surprise us if the resonance effect in the Bay of Fundy (also called a "seiche") responded non-linearly to sea level rise. We suspect this is, or will be, an area of active scientific research. Especially since critical infrastructure in that part of the world is not far from today's high water position.
What would happen if we dropped the moon on earth from 10m? It seems to me that small masses are unable to cause the earth to move significantly.
It would seem when dropping a mass that is approximately 0% of the total mass, that only a single object needs to be thought as moving.
And we are always dropping multiple objects that are approximately 0% of the total mass and they appear to land at the same time.
But again what happens if we dropped something that had 30% of earths mass?
Or what would happen if we instead dropped a ball and feather onto a ball of equal mass as the 1st ball?
It would also seem to depend on how you dropped the objects as if all three are in free fall they would fall to a center of mass common to the 3 masses.
I would think the 2 bodies with the highest energy would collide first.
It just seems that we can say the mass of what is falling is not important when a single mass dominates all other objects.
It would seem we would need to drop small objects from a much further distance to notice a slight amount of difference in “drop” times.
@@cybermonkeys sorry this question was not about tides. I got to the part of the video where they talking about gravitational acceleration. And acceleration only being dependent on a single mass.
I would think the acceleration would be dependent on the total mass or total energy.
Thank you for the information though.
It seems to me that when we drop objects near earth to observe the effects of gravity we are in a unique scenario where a single mass dominates. I am just curious what would happen in a vacuum outside of the earths gravitational field if we dropped objects where a single mass did not dominate.
@@cybermonkeys thanks I will look into that. I did not make it past this part of the video because I was annoyed with this simplification. I do enjoy me some Dr. Becky so I will look for that video.
Thanks for the response,
Have a wonderful day as well.
@@cybermonkeys I just find that sometimes when things are simplified detail that was not important in the original situation is ignored. But it is not always insignificant in all situations. I want to know the conditions where it can be ignored and potentially where it cannot and why.
Without understanding the fine detail one is limited to applying what has been learned into identical situations only. I prefer to learn the detail so I can adapt what I have learned to a wider variety of conditions.
Again thanks for the insight and direction. The other videos were good.
@@cybermonkeys sure you can use my thoughts or questions. I do love some Mars “Bringer of War” and Jupiter “Bringer of Jollity.”
This was very interesting and so well put together. Thank you for contributing 👌
Stoked you enjoyed it, we've got more videos like this in the works. Stay tuned
7:22 We should have hit the moon by now…!?
This was an awesome explanation, clear and everything thank you!!
A rather poor explanation of the tide on the opposite side to the moon. Both Earth and Moon rotate about the barycentre of the Earth-Moon system. This point is not at the centre of the Earth, rather nearer to the side facing the Moon, about 4700 km from the centre of the Earth. The far side of the earth is then rotating around the barycentre, which explains the lower tides on that side.
I'm a diver and this was a phenomenal video
turn the music down!
Thank you very much for the video. I felt like a piece of a puzzle clicked to it's place in my head. And this is very satisfying.💡
I thought that the primary tides were caused by the earth rotating around the centre of mass of the Earth - Moon system, the center of mass being about 1/3 of the earths radius in from the surface - on the same side that the moon is at any time. Then we have water being flung from the earth and attrated to the moon on one side, and water being "flung out" on the side opposite to the moon creating out diurnal tides. Then the sun has a similar but smaller effect, these two interactions then "beating" to give the neep and spring tidal variations in tidal heights. Oh and apparently Jupiter has around a 1% effect on our tides. ua-cam.com/video/Mr89IgzsMVk/v-deo.html
@@oortcloud8078 I've attached her !!!