This principle humbled me as a young scientist and student pilot. I thought I knew everything, that I had an intuitive grasp of basic physics. It took me a long time to wrap my head around this one principle.
It seems to make more sense for me to realize the air being blown is sticky and grabs the air from the side tube and pulls it along. Mayne not correct but hey I'm just a regular joe
I've just finished reading James Burke's superb book Connections, which I would recommend to anyone interested in the history of scientific ideas. In this book he explains how this principle was used to create carburettors, making possible the internal combustion engine and jet engines, and how the principle it could be used to measure the flow of a gas through a pipe. However, limited space only allowed him to give a brief overview of these things. The excellent demonstrations in your video make it easy to get my head around these concepts.
This phenomenon is one of the most mind- fucking results in all physics to me. The fact that blowing air with high pressure through a tube with a restriction causes the air to decrease in pressure at the restricted part is so counterintuitive. My brain just will not understand how increasing the space in which a fluid can flow causes the pressure of the fluid to increase and vice versa.
I have no PhD in physics so this may just be my 2am thoughts. I think what it's referring to specifically is the amount of air it takes to make the force. Like 150 psi is different through a straw as opposed to a 2 inch round tube. So hypothetically let's just say I would need a compressor to generate 150 psi through the tube where as I could just blow through the straw myself and make 150 psi.
I’m guessing the pressure increases at the part of the tube where it gets squeezed. Not the part where it is already squeezed. In fact. That would explain why the pressure reduces because the narrowest part is the outlet of the compressed air
Unfortunatly, it is WRONG. Please make corrections or remove it. .. The statements about Bernoulli's Principle are correct, but the demonstrations are very poor. The balls, spoon and funnel are a result of the Coanda effect. . The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube. .. To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface. .. At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
demonstrating college level fluid dynamic physics with plastic and a cheap blower. I applaud your ability to demonstrate what so many professors rely on overly complicated texts and complex mathematics to explain. BRAVO!
@@getaclass_physics But it is wrong: This video is still WRONG. Please make corrections or remove it. .. The statements about Bernoulli's Principle are correct, but the demonstrations are very poor. The balls, spoon and funnel are a result of the Coanda effect. . The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube. .. To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface. .. At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
@@Observ45er While your first point is true, and the ball sticks only due to the coanda effect, the other points are only partially correct. The low pressure in the thin section of the pipe is the main reason the water flows upwards. The curve around the small pipe head directs a negligible amount of air to the top, most of it just goes around it, even if all of it was directed to the top, it not be near enough low pressure air to pull the water out.
@@SomeRendomDude Unfortunately, that demo is seriously flawed because the vertical "draw tube" is sticking up INTO the flow. It is not sensing the static pressure of that section. It would draw water up if the horizontal pipe was not there. To properly sense the static pressure, the draw tube must not disturb the flow. It must be an opening flush with the inside surface of the pipe. This is just another clear example of people trying to demonstrate something they do not understand - -THEN stumble onto something that appears to confirm their flawed hypothesis. . . What he has there is a true Atomizer that was used in perfume bottles. The flow hits the tube end and causes a curved flow over the top and around the sides. I have done carefully designed experiments to show this very fallacy. See this correctly interpreted Millersville experiment: ASPIRATORS CURL www.millersville.edu/physics/experiments/093/ .. Weltner explains how to make a static pressure probe here: FIG 3 Static Probe: www.researchgate.net/publication/303974495_Misinterpretations_of_Bernoulli's_Law
One of the clearest explanations of Bernoulli's Principle that I have seen. Everything very well explained, and many examples showing how everything works. Thank you very much!
The interesting part is that if you close the system, when you blow, pressure increases. However, when you open so that the air can flow, the pressure decrease the faster it goes.
Be careful. The way you stated it is not true. As you turn up the blower to increase the speed of the air-jet out of that blower, the static pressure of that jet of air coming out of the blower remains at atmospheric pressure. That is why it exits the blower. The higher pressure inside the blower accelerates it out into atmospheric pressure. That is where we see 'Bernoulli' happening. . When you add the surface of the ball, you are changing the conditions and it is the curve of the flow that is causing a lower pressure near the surface.
@@Observ45er I'm not talking about closing the system with a ball that can open like in the video. I'm talking about sealing the exit hole completely.
@@xdragon2k I can't make sense out of what you are proposing. . You said: "when you open so that the air can flow, the pressure decrease the faster it goes." . I'm talking about a blower pointed to the open air. Nothin closed about it. . What is "open".
@@Observ45er I'm talking the counter intuitive nature of blowing into a container that is usually spread the container apart like a balloon because of increased air pressure, vs blowing through something that is open ended reducing the air pressure in the airflow and constricting the container.
@@xdragon2k I very am very sorry, but your English is not good enough for me to understand. . Rereading your original it appears you are comparing two thigs. 1} Blowing into a container such as a bottle. When you do this you increase the pressure in the bottle. YES. . 2} Blowing into a pipe that has a wide section, then a narrow section then a wide section - a venturi, Then the pressure in the narrow section is lower than the wide sections. . . That;s the way it works.
Comical. EVERY video on this topic has the exact same explanation: "narrower the pipe section, the lower the pressure" because equations . What happens is equations due to more equations . HOW does it work? By equations .
@@billshiff2060 Buddy, the equations explain exactly why this occurs. The velocity of the fluid increases as it travels from a wider region to a narrower region, as the work done by the fluid is down a pressure gradient. Therefore, the fluid must flow from a region of a higher cross-sectional area to a narrow cross-sectional area in order to increase its velocity, and this would naturally cause the pressure exerted by the fluid to decrease. Mathematical equations simply explain this phenomenon through variables instead of words.
@@weltschmerzistofthaufig2440 So your explanation is, it is caused "naturally" + equations. No mention of particle velocity, which IS the cause of pressure, is ~ mach 1.5 regardless of where it is and yet the pressure decreases in smaller passages.
@@billshiff2060 Are you saying that Bernoulli’s principle doesn’t work? I could use kinetic particle theory to explain it, but I instead focused on macroscopic observations and mathematical evaluation to explain this. Also, who told you that particle velocity remains the same? In fact, in a narrower section, the total number of collisions between particles and the container would decrease as the work done by the fluid occurs in the direction of movement. Thus, a pressure gradient must exist to ensure that there is an increase in kinetic energy in a narrower region.
Muito boa a explicação. Obrigado! Para quem não entendeu o final, em 4:50 a velocidade é calculada dividindo o "volume de ar por segundo" (12 l/s = 12000 cm3/s) pela "área da seção" (3 cm2) = 4000 cm/s = 40m/s
So... the two balls were "sucked" towards each other because the two balls created a small channel for air or water to pass, thus creating lower pressure compared surrounding space (atmospheric pressure). This lower pressure in this smaller channel creates a vaccum, pulling the balls together.
it's not the vacuum that pulls the balls. You've said it: it's the atmospheric pressure that pushes them. __ for a 3 cm radius sphere we get about 1 N: P=f/A; f=PA = 101 Pa * 4Pir^2 =101*0.0113=~1 N
I'm a kindergarten teacher. Every Friday, we make a science toy. Other teachers in my school just say "Ok, let's make today's toy." I don't. In my class, we learn why it works, how it works. Ok, at kindergarten level, but it can be done. We have a toy each year that uses the Bernoulli principle of the ball in the cone. We use a plastic kitchen funnel and a straw, with a polystyrene (styrofoam) ball. I get the kids to color one half of the ball with a felt pen. That helps us to see how the ball moves. By watching the ball's movement, we can start to understand the airflow. That's when I link it to light bending around stars, or black holes. It's by looking at what you can see that you understand what you can't see.
In realms of air where wings take flight, A dance of forces, pure and bright. Bernoulli whispered secrets old, In currents swift, a tale unfolds. Above, below, a magic play, In skies where dreams find their own way. A symphony of pressure and speed, A waltz unseen, the laws decreed. As air flows, it weaves a song, A melody where forces throng. Upon the wings of birds in flight, Bernoulli's dance, a graceful height. At curves and bends, in fluid grace, The air, a partner in this chase. Velocity and pressure dance, In every move, a sweet romance. From wings that lift to planes that soar, A principle forevermore. In tubes, in winds, in rivers wide, Bernoulli's truth, an endless guide. A theorem sung in skies so blue, In clouds and dreams, forever true. A whispered secret, nature's rhyme, Bernoulli's principle, through space and time.
But WRONG. The statements about Bernoulli's Principle are correct, but the demonstrations are very poor. The balls, spoon and funnel age a result of the Coanda effect. . The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube. .. To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface. .. At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
Very simplified demonstration of the basic principle of Bernoulli .I wish some body could have explained me in my school level in such a lucid language.
Clip này thực sự đã chạm đến trái tim mình. Bạn đã truyền tải những cảm xúc về tình yêu, lòng kiên nhẫn và sự bao dung một cách rất chân thành và tinh tế. Đây thực sự là một video có giá trị nhân văn cao mà mình tin rằng ai cũng nên xem để suy ngẫm về cuộc sống và cách đối xử với nhau.
I understand that Bernoulli's Principle exists, but I'm still trying to understand why it exists given the molecular nature of the fluid. The two things I'm trying to reconcile: - The fluid when constricted moves faster, so there is a force (pressure) experienced by that fluid from the direction of flow. - There can be fluids (e.g. the air in the bottle at 3:10) or objects (e.g. the ball at 0:42) external to the closed system that when they interact with this system they experience a lower pressure near the flowing fluid. I may be able to come up with a molecular explanation* for other fluids adjacent to the flowing fluid experiencing a lower pressure (0:42) or even the two metal balls being pushed together (0:22), but the rubber ball experiencing lower pressure when it is directly in the flow direction of the fluid (3:10) is breaking my explanation. *The intuition of the idea is to first start at an extreme: the fluid is moving so quickly that any other fluid that finds itself wandering into the pay is swept away. That said, I don't see how this intuition can be used to explain the rubber ball (3:10).
So many people who try to go to the molecule level make similar errors. The molecules are in thermal motions that are hypersonic! They are bouncing amongst each other at speeds FAR, FAR, FAR, FAR faster than any of this is happening. Those motions continue and there is only a drift that is added, vectorially to those motions. It all acts like a continuous medium. It is just the incessant pounding of the vibrating molecules that makes pressure on each other and surfaces. .. YES. The fluid is Accelerated away from the higher pressure - slower region, TOWARD the lower pressure - faster region. That flow, then HAS that very SAME lower internal pressure. . . . It is the pressure difference, called a Pressure Gradient, that provides the Accelerating force on the fluid's mass. Think of a brick with two, opposite-facing forces applied. If one is greater than the other, there is a net force and the brick will Accelerate toward the smaller force. RiGHT? . That bricks Acceleration is NOT CAUSING that smaller force. . . .. Well, when there is a pressure difference between two locations, the higher pressure pushes more and accelerates air toward the lower pressure. Euler is credited with figuring this out when he followed up on Bernoulli' work. According to John D. Anderson's Text on Fluid Dynamics, there is no indication in Bernoulli's notes that he understood the cause and effect. He only knew that the speed increase WAS ACCOMPANIED BY a pressure decrease. . Bernoulli "happens" in a balloon that is venting to the atmosphere. Or your lungs when you blow. The "high" pressure inside the balloon/lungs, push more than the atmospheric pressure outside the balloon/lungs. That is a Pressure Gradient (in fluid dynamics terms). The Higher potential energy inside is converted to the higher kinetic energy outside - where that "fast" jet of air IS AT the AMBIENT atmospheric pressure . . THE JET IS NOT, NOT, NOT below atmospheric pressure. NOT BELOW!!! . . P.S. The Ball in the funnel is Coanda as the air curves around the ball, lowering the pressure where the funnel is nearest the ball, thus a lower pressure toward the smaller end of the funnel. Just about all the bad demos are due to Coanda causing pressure reduction, NOT the "fast" air. . . Sigh. . . . The TWO balls is the SAME thing - Coanda. When air flows along a convex surface, the pressure near the surface decreases because of INERTIA. Air has mass. Fundamental property of mass is inertia. Air traveling along ball surface is being held agains the surface by atmospheric pressure - LOTS of it!! As the surface curves away from the straight path, Inertia 'wants' to go straight and, in effect, "pulls away from the surface - INERTIA works against atmospheric pressure, therefore pushing less on the surface. See the video in my Blog. The Roller coaster analogy it 100% identical to flow along a convex surface. This is SO frustrating with every one repeating this nonsense. . . .. Here is my Blog that steps through all this physics correctly and the misconceptions. . . BLOG: *Understanding Bernoulli and Aerodynamic lift Correctly:* rxesywwbdscllwpn.quora.com - - Good luck and Happy new Year.
The correct term is to say `Bernoulli's' Integral', since it is just an integral of the Euler's equations of motion for a particular case of steady, inviscid and potential flow. The term `principle' is related to something very fundamental, like The Principle of Least Action etc.
That name is popularly known by people. You can get the same equation by cancelling viscous terms and triple integrating Navier-Stokes' momentum equation. If I can do that, then it should be called the Navier-Stokes-Bernoulli equation, and it's not that A name is just that, a name, so people can easily recognize the equation
The pressure reduction is due to the expanding exit and not the narrow part of the system. The width of the entry may not be important but the exit, the wide exit creates a sudden increased volume hence the reduced pressure. I would like to see the same experiment be done without the expanding exit and see if there will be any differences
The exit or diffuser has been measured (not estimated) countless times to have increase in pressure, the negative peak of pr3ssure coefficient is at most right before it, if your brainstorm was close to right the entire racing industry would be incorrect.
No, that is not Bernoulis principle. As she explained, the product of mass and velocity equal a constant, such that if you increase the velocity, pressure must decrease to maintain the same energy in the stream. It has nothing to do with what happens further downstream. You are confusing this with what happens when you pulse the pressure of a compressable gas, there are waves of low pressure radiating from the convergent and divergent sections. This is used in two stroke exhaust systems known as expansion chambers.
Excellent presentation thanks a lot...beautiful presentation of the bit difficult concept to explain the students.....really....it is made too much easy......by you.....briliently simplified by demonsyrations and last photo of Actually venturimeter is also most important....Thanks a lot to All of you who have made Physics simple🙏
Fascinating video. However, I am not sure that the ball hanging in the water coming from a tap is really demonstrating the Bernoulli principle. Firstly, the water is not being constrained to flow through a narrower channel - it is free to flow over the surface of the ball and so the cross section of the flow is probably not reduced. Secondly, if you look at the flow of water coming off the bottom of the ball, it is deflected to the right after it has flowed over the surface of the ball. Changing the direction of the water flow to the right causes a reactive force on the ball towards the left, and this is probably what makes the ball appear to cling to the water - the ball comes to a rest where this leftward force is balanced by the rightward force of the downward water flow pushing on the ball.
I agree that the ball in the running water was not explained right or enough. But I think they meant that the change in the pressure of AIR around the running water causes the movement of the ball, not the pressure of the water. For some years now I have wanted to know why the spoon is pulled by the running water. And to me it looks like the curved shape plays the major role. I doesn't happen when you rinse a knife.
@@sylwiagotzman5422 Have a look at the video: Why are so many pilots wrong about Bernoulli’s Principle? by Fly with Magnar (ua-cam.com/video/uyRx25MSWng/v-deo.html). IMO he explains quite well what you're describing, it is the same as for an airfoil. Spoiler: it is also Bernoulli's Principle, and has indeed to do with acceleration of the fluid at the convex part of the spoon
It's the Coanda effect, not Bernoulli's Principle, that pulls the spheres or spoons together in a liquid or gas flow. The experiment would not be able to be replicated with cubes instead of spheres.
The amazing thing is, there were no electric blowers in Bernoulli's time, heck, there wasn't even electricity ! And heck, there wasn't even a faucet as we know it ! What a freaking genius mind is this, how did he figure out all of this ??
I think that this didn't explain the nature of the effect - the *behavior* of the particles (or strings) in flow relative to "stationary" ones. A part two to the video, with particle animation, where you visualize the pressure exerted by particles which do not flow is very much needed in my opinion.
Unfortunately it is wrong. . . . This video is still WRONG. Please make corrections or remove it. .. The statements about Bernoulli's Principle are correct, but the demonstrations are very poor. The balls, spoon and funnel are a result of the Coanda effect. . The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube. .. To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface. .. At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow. . . . . This shows the proper way to measure static pressure within a flow: Weltner Direct link: still valid on June 24 224: “Misinterpretations of Bernoulli's Law by Klaus Weltner, University of Frankfurt (G)” FIG 3 Static Probe: www.prirodopolis.hr/Bernoulli-Coanda%20Demo_files/Misinterpretations%20of%20Bernoullis%20Law.pdf . .
I have always had difficulty providing an intuitive explanation for this phenomenon, but if we try to think of pressure as potential energy rather than force per unit of surface area, perhaps the concept becomes a bit more intuitive. Or, imagine having a blown-up balloon. The balloon has a certain internal pressure. When the balloon is opened, the air inside the balloon starts to move faster. The internal pressure of the balloon then decreases because the potential energy of the air inside the balloon is converted into kinetic energy.
I just wish someone would taught me like this when i was young.. when UA-cam was not that much a big hit and we had to pay exorbitant prices for just 1GB of internet data in India at that point of time we had to imagine all we could.. but now seeing this animated video with real life examples is what giving me an epiphany that what i imagined at that point of time was correct…
The seemingly stationary yet the active atmosphere around the two-ball system pushes the ball to come together when the air in between them is displaced. Though the atmosphere tries to fill in the gap again with air, the continuous removal of air makes the balls stick together and the direction of the displacing pressure dictates the direction of the balls' rotation.
By slowly pressing a box internal pressure would rise and the walls of box would heat up. Box would remain pressed in position that force heat of walls and heat of walls would be collected for electric energy production or for heating , keeping the box in pressed position would be done whit some closed brackets so no input of energy for keeping the box pressed so all its heat would be used to produce output of energy
An Air brush functions by a certain velocity of air passing laterally down a tube of said diameter - at a mid point down the tube is a T- piece with a pipe leading to a semi liquid media /paint source - A pressure is formed at the pipe perpendicular to the main pipe due to currents being generated by the air flowing through the lateral pipe. The flow of current in turn causes a vacuum at the pipe perpendicular to it. - With a carburettor this is called down-draft. Its basically a pressure created by many things travelling at speed - Aircraft, Cars, Speed Boats - - If you have wondered why if you leave your tail gate open you get chocked by exhaust fumes being sucked back into the car.
Oh! So for the thing at 3:00 it doesn't matter if it's an airblower or a vacuum, since it's symmetrical anyway, which can more intuitively explain why it sucks up the liquid
I really LOVE this video Back in the 80s we had Bernoulli Boxes These were large (for the time) memory disks using the Bernoulli principle I know you have a large queue of ideas, but could you please put a video talking about this video along with one explaining the Bernoulli Box?
Pressure and Flow = volume per minute - Just like voltage and current = watts. The amount of output remains the same even though you are changing the ratio of pressure to flow.
Randomly stumbled to this video and thankfully I clicked it. Now I understand how the soap get used when my father use the his pressure washer with bottle of soap on the water gun.
The video is great and makes it clear how the pressure works for air and liquids and such, but how would the joined trumpet shapes react to sound. If one half is similar to the old ear trumpets that increased the sound, is this saying that the increase in sound is similar to the speed pf water, and that the increase in sound is matched by a decrease in some other quality of sound.
conservation of energy is a weak explanation because it does not explain why the fluid accelerated into the narrow section. Fluid has mass and a force is required to Accelerate a mass, so what is the force and what is the source of the force?
Your test tube is after the smallest opening, so the pressure is decreasing. The pressure increases to the maximum AT the smallest opening. It increases, then decreases suddenly like a divergent rocket nozzle trading pressure for flow/thrust. Like a transformer trading voltage and current with the power being the same except for the small loss of the transformer.
This video is WRONG. The statements about Bernoulli's Principle are correct, but the demonstrations are very poor. The balls, spoon and funnel age a result of the Coanda effect. . The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube. .. To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface. .. At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
2:30 try turning it around tho’. The air must have lower pressure than outside the tube…but the straw will experience +ve pressure because it is upwind of the narrowest part.
What about the pressure at the point where it starts its path to being a smaller diameter. Wouldn’t the pressure be higher at that point. I get the draw and vacuum at the end of the smaller diameter back to large but the pressure must increase at the direction of the flow where it’s going from larger to smaller. The pressure has to increase.
what I think of this is that when air is blown very fast at sudden high speeds, pressure over there decreases because you just removed a given volume of air from that part. The speed at which this is happening, causes air, fluid or any solid to get attracted towards that part of the empty space due to partial vacuum. As we know, fluid will always try to fill empty space. In that case, since fluid from the surrounding area is trying to fill that empty space, solids surrounded by that part of fluid is pushed into it(given the solid isn't heavier than the force exerted due to pressure of the fluid) and hence we get this. In the same way, the volume of air flowing between 2 planes when they are near(due to the 2 engines next to each other) being pushed backwards is so high, that it creates partial vacuum between them and a slow attraction force(or u can say force due to fluid[air] at a higher pressure) surrounding the planes pushes them while trying to flow into the temporary partial volume of emptiness. I hope this explanation helps anyone who wants to understand this principle or visualize it.
When moving at considerable speed, this principle becomes tactile; breathing with wind-force against ones face 'should' make inhalation easier by intuition; however it is not the case, the faster the wind approaching ones face the harder it is to inhale, in-fact the lungs volume is wrenched from ones throat instead, and only an eddy-of air-pressure will allow ones respiration at-speed.
It's not true that faster air flow implies lower air pressure. Bernoulli's Principle only says that a faster section of flow within the same fluid flow must have lower pressure than a slower section within that same flow. If you stick your head out of a fast moving car and face forward, it should be easy to inhale.
I dont believe this proves the air pressure in the main tube gets lower .the apparent suction is possibly caused by the airflow across the end of the little pipe inserted. in the same way wind draws smoke up a chimney. The weight and velocity and friction of the moving air in the big constricted tube causes this. Another way to test the hypothesis is to blow air through a soft plastic tube with a constriction and see if the constriction expands or closes. A very soft tube of thin plastic would probably ripple vacilating between open and closed is my guess.
That is not a "paradox" nor "counterintuitive". That is a quite simple relation emerged from energy conservation principle... If you're struggling with these, perhaps you got confused over the "pressure" term - when velocity increases, the STATIC pressure is the one that decreases.
Hello. This is partially miss informative ! The Bernoulli theorem is challenging, but it kind of makes sense in a CLOSED system. You could think of it in lines of that you have roller coaster carts attached with springs. As they start rolling downhill the speed increases and the cart in front is pulling the spring to the next cart and vice versa. When they are slowing down uphill ... the springs compress (higher pressure) when the speed decreases. Now when you start blowing stuff in to the surrounding atmosphere it gets messy. The two spears getting drawn together, it is because of the coanda effect. The pointed jet sucks the surrounding air with it and creates a low pressure. NOT to do with Bernoullis principle. I know; It is complicated :). The ball hanging under the water flow, counter intuitive or not has to do with the coanda effect, i.e. water being sticky and curving around the ball, hens creating an opposite force to the curving acceleration. Oh well. Always have doubt, if your intuition says that something is not necessary so ;) .
Finally someone pointed it out! There are so many misinterpretation regarding Bernoulli's Principle. It has rather strict assumptions for the fluid and the system (closed system, inviscid, incompressible, irrotational, no external force other than gravity etc.) and is not what people think it is. Another wide spread rumor is that lifting force of a plane can be explained by Bernoulli's Principle. It is so wrong that NASA specifically wrote an article titled "Incorrect Lift Theory" for it: www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/wrong1.html Most videos claiming to be showing Bernoulli's Principle are NOT doing it under correct assumptions. Sigh.
Thank you for your effort, but you're assuming the surface is (or that it even could) pulling the air towards itself which is blatantly false, Coanda is a mere observation that air tends to follow the surfaces which is false as soon as flow separates, and it works on water because 1- surface tension and 2- water is much denser than air. All aerodynamics forces are pressure driven, like Newton on fluids, which is the correct way of visualising it.
@@davidaugustofc2574, the Coanda effect also occurs with air (not just water) flowing over a curved surface, and is the reason for the spheres being pulled together with air flowing in between and for the sphere being pulled into the water flow. The same result does not occur if you use cubes instead of spheres. Those experiments do not exemplify Bernoulli's Principle, which applies to a single fluid flow. It is the pressure difference that causes the velocity difference, not the other way around.
@@mattcarter1797 My problem with the Coanda effect is that it is a gross oversimplification of the entire thing. You need to understand a little bit from several topics to understand what it really means, and those topics are more helpful than the conclusion. Air is mostly neutrally charged, as gas molecules usually are, so the external electron layers will repel each other, a gas would expand to Infinity if it had a chance and enough time. However, due to the local, gravitational effects from the Earth, the air is squeezed together, and the balance of those is the atmospheric (sometimes known as static) pressure. Gravity makes it so that pressure is very even for the same height all across the globe (temperature changes aside), so when a moving body is going through air and changing the pressure around itself, there will be a restoring force acting on the fluid to bring the new pressure value back to the original one. That is pressure will flow from high to low until there's negligible difference between the areas. When the air gets close the surface it's pushed away by the first layer, that's attached to the surface due to friction, and when the surface curves away from the direction of flow it forms low pressure pockets that will exert less force on the surface and nearby molecules that the air surrounding it, thus guiding the air towards the surface. (Greatly helps if you have a way of visualising it) And that's very simplified in it's own rights, since vorticity is a humongous topic on it's own, that I haven't even touched. I cannot understand how we're helping people by telling them about the Coanda effect and not the reasons behind it, you can't really learn anything from it. Okay, it was a great discovery for their time, but we're now at a stage where computers can generate airfoils from a set of requirements, we need to point out that air tends to follow surfaces and move on to deeper topics and not keep hanging on to it as explanation for anything.
5:20 Isnt then the amount of gas the travels through the pipeline limited by that section? Its confusing. I think no, as the gas can be pressed through. Doesn't this then create a temperature difference, where the thinner part gets warmer and after it its colder than average?
As the speed of the air increases the ball redirecting the air has a boundary layer that causes the air to follow the curved surface . Air has weight . The air is acting under the laws of Centrifugal force as it is held to the ball by the low pressure boundary layer and causes what we call lift. Air accelerated across a curved surface "wing" creates lift by the weight of the centrifugal force directly relative to the speed . The faster the wing through that air the faster the air has to move to follow the wings surface which creates centrifugal force by kinetic energy. A wing flying just above VSO can not be over stressed . But above VNO can be overstressed easily . More airspeed across the wing more centrifugal force the air creates on the boundary layer. Such an experiment if I remember correctly was conducted on an F16 wing with a porous top wing surface where more vacuum was introduced I would suppose to slow the stall break. Boundary layers lifts NOTHING . It is the area between the wings surface and the fluid movement of air which can not do anything above VSO but adhere to the upper wing surface curvature creating a vacuum across the wing . The blunt nose of the wing along with angle of incidence only accelerares that air. The Whittman wing for the Tail wind has a thin wing with a sharp leading edge thus high take off , stall and flying speed. Ultralights use a very rounded leading edge to compress the air flow across the wing this a low stall speed .
👉 3:00 This principle solves the problems of empty nose 👃 syndrome, allowing the paranasal sinuses to be emptied and the viscous secretions of the middle and upper meatus to be cleaned, improving nasal physiology and breathing. Maintaining internal humidity in the Oropharynx.
Bernoulli explained this a long time ago. If an incompressible fluid flows out, then the flow velocity and pressure are related by the relation: p+ro*v^2/2 = const (constant) The conclusion is simple: the more the hose is pinched, the farther the jet flies.
But isn't it more like the pressure of the fluid of the restricted section increases, while the pressure exerted by the fluid on its containment decreases? If you observe this principle in water coming out of a pressure washer, then the smaller and tighter stream exerts more force on any object it encounters. The pressure within the restricted stream of water is higher and it creates a low pressure boundary of air surrounding it.
No, Chris. Your simplified thinking has led you astray. . As the fluid flows TOWARD the inward sloping wall sections, the flow is TOWARD those walls and, therefore pushing more on them. It is similar to a wind that pushes more as it tries to approach a surface or blow you down. . Then, a fundamental fact of fluids is that pressure at any given point pushes outward in ALL directions. . That pressure against the wall is also eithin the fluid and it 'communicates' both inward and backwards, upstream and increases the pressure in the FAT section on the left. >>The reduction in diameter CAUSES the UP-STREAM pressure to increase.!.
This principle humbled me as a young scientist and student pilot. I thought I knew everything, that I had an intuitive grasp of basic physics. It took me a long time to wrap my head around this one principle.
Good to hear! We should never assume that we know everything of anything. This video was indeed quite intersting.
It seems to make more sense for me to realize the air being blown is sticky and grabs the air from the side tube and pulls it along. Mayne not correct but hey I'm just a regular joe
Yes, that’s a good way to think of it. It makes more logical sense to me the way you’ve described the ‘sticky air’. I’ll remember that.
This is literally what I study in Highschools. This principle is one of the basics.
Physics is the discipline where math proves common sense totally wrong.
Same thing happens when high-pressure information passes through my low-pressure brain
What, it pushes your balls together? (sorry; couldn't resist)
lol
😅😅😅😅
😂😂
😂😂😂😂
I've just finished reading James Burke's superb book Connections, which I would recommend to anyone interested in the history of scientific ideas. In this book he explains how this principle was used to create carburettors, making possible the internal combustion engine and jet engines, and how the principle it could be used to measure the flow of a gas through a pipe. However, limited space only allowed him to give a brief overview of these things. The excellent demonstrations in your video make it easy to get my head around these concepts.
The TV series Connections is superb, as well. I highly recommend it.
@@marcochimio I remember them as a kid... when TV was informative, and not just propaganda.
@@sunnyjim1355 thankfully yt is here to fill the void! havent watched tv in years
This phenomenon is one of the most mind- fucking results in all physics to me. The fact that blowing air with high pressure through a tube with a restriction causes the air to decrease in pressure at the restricted part is so counterintuitive. My brain just will not understand how increasing the space in which a fluid can flow causes the pressure of the fluid to increase and vice versa.
Exactly!!!!
you got it right
I surrendered and decided that nature obeys to maths.
I have no PhD in physics so this may just be my 2am thoughts. I think what it's referring to specifically is the amount of air it takes to make the force. Like 150 psi is different through a straw as opposed to a 2 inch round tube. So hypothetically let's just say I would need a compressor to generate 150 psi through the tube where as I could just blow through the straw myself and make 150 psi.
I’m guessing the pressure increases at the part of the tube where it gets squeezed. Not the part where it is already squeezed.
In fact. That would explain why the pressure reduces because the narrowest part is the outlet of the compressed air
Great demonstrations of Bernoulli's principle! Seeing the effect in action helps to understand it.
Unfortunatly, it is WRONG. Please make corrections or remove it.
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The statements about Bernoulli's Principle are correct, but the demonstrations are very poor.
The balls, spoon and funnel are a result of the Coanda effect.
.
The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube.
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To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface.
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At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
demonstrating college level fluid dynamic physics with plastic and a cheap blower. I applaud your ability to demonstrate what so many professors rely on overly complicated texts and complex mathematics to explain. BRAVO!
Glad you enjoyed it!
@@getaclass_physics But it is wrong:
This video is still WRONG. Please make corrections or remove it.
..
The statements about Bernoulli's Principle are correct, but the demonstrations are very poor.
The balls, spoon and funnel are a result of the Coanda effect.
.
The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube.
..
To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface.
..
At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
@@Observ45er While your first point is true, and the ball sticks only due to the coanda effect, the other points are only partially correct. The low pressure in the thin section of the pipe is the main reason the water flows upwards. The curve around the small pipe head directs a negligible amount of air to the top, most of it just goes around it, even if all of it was directed to the top, it not be near enough low pressure air to pull the water out.
@@SomeRendomDude Unfortunately, that demo is seriously flawed because the vertical "draw tube" is sticking up INTO the flow. It is not sensing the static pressure of that section. It would draw water up if the horizontal pipe was not there.
To properly sense the static pressure, the draw tube must not disturb the flow. It must be an opening flush with the inside surface of the pipe. This is just another clear example of people trying to demonstrate something they do not understand - -THEN stumble onto something that appears to confirm their flawed hypothesis.
.
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What he has there is a true Atomizer that was used in perfume bottles. The flow hits the tube end and causes a curved flow over the top and around the sides.
I have done carefully designed experiments to show this very fallacy.
See this correctly interpreted Millersville experiment:
ASPIRATORS CURL
www.millersville.edu/physics/experiments/093/
..
Weltner explains how to make a static pressure probe here:
FIG 3 Static Probe:
www.researchgate.net/publication/303974495_Misinterpretations_of_Bernoulli's_Law
One of the clearest explanations of Bernoulli's Principle that I have seen. Everything very well explained, and many examples showing how everything works. Thank you very much!
The interesting part is that if you close the system, when you blow, pressure increases. However, when you open so that the air can flow, the pressure decrease the faster it goes.
Be careful. The way you stated it is not true. As you turn up the blower to increase the speed of the air-jet out of that blower, the static pressure of that jet of air coming out of the blower remains at atmospheric pressure.
That is why it exits the blower. The higher pressure inside the blower accelerates it out into atmospheric pressure. That is where we see 'Bernoulli' happening.
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When you add the surface of the ball, you are changing the conditions and it is the curve of the flow that is causing a lower pressure near the surface.
@@Observ45er I'm not talking about closing the system with a ball that can open like in the video. I'm talking about sealing the exit hole completely.
@@xdragon2k I can't make sense out of what you are proposing.
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You said: "when you open so that the air can flow, the pressure decrease the faster it goes."
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I'm talking about a blower pointed to the open air. Nothin closed about it.
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What is "open".
@@Observ45er I'm talking the counter intuitive nature of blowing into a container that is usually spread the container apart like a balloon because of increased air pressure, vs blowing through something that is open ended reducing the air pressure in the airflow and constricting the container.
@@xdragon2k I very am very sorry, but your English is not good enough for me to understand.
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Rereading your original it appears you are comparing two thigs.
1} Blowing into a container such as a bottle. When you do this you increase the pressure in the bottle. YES.
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2} Blowing into a pipe that has a wide section, then a narrow section then a wide section - a venturi, Then the pressure in the narrow section is lower than the wide sections.
. .
That;s the way it works.
Best explanation of Bernoulli's principle I came across on internet. Thank you so much!!
Comical. EVERY video on this topic has the exact same explanation: "narrower the pipe section, the lower the pressure" because equations . What happens is equations due to more equations . HOW does it work? By equations .
@@billshiff2060 Buddy, the equations explain exactly why this occurs. The velocity of the fluid increases as it travels from a wider region to a narrower region, as the work done by the fluid is down a pressure gradient. Therefore, the fluid must flow from a region of a higher cross-sectional area to a narrow cross-sectional area in order to increase its velocity, and this would naturally cause the pressure exerted by the fluid to decrease. Mathematical equations simply explain this phenomenon through variables instead of words.
@@weltschmerzistofthaufig2440 So your explanation is, it is caused "naturally" + equations.
No mention of particle velocity, which IS the cause of pressure, is ~ mach 1.5 regardless of where it is and yet the pressure decreases in smaller passages.
@@billshiff2060 Are you saying that Bernoulli’s principle doesn’t work? I could use kinetic particle theory to explain it, but I instead focused on macroscopic observations and mathematical evaluation to explain this. Also, who told you that particle velocity remains the same? In fact, in a narrower section, the total number of collisions between particles and the container would decrease as the work done by the fluid occurs in the direction of movement. Thus, a pressure gradient must exist to ensure that there is an increase in kinetic energy in a narrower region.
@@weltschmerzistofthaufig2440 Who told you that particle velocity varies?
Please make more videos. 🙏
Doing so will increase the likelihood of young minds coming across valuable information such as this.
🧠🧠🧠🧠🧠🧠🧠🧠🧠
Beautifully explained. One of the best videos on Bernoulli's principle on UA-cam.
Muito boa a explicação. Obrigado! Para quem não entendeu o final, em 4:50 a velocidade é calculada dividindo o "volume de ar por segundo" (12 l/s = 12000 cm3/s) pela "área da seção" (3 cm2) = 4000 cm/s = 40m/s
This video is awesome! It explains teh principle in a simple way, as well as showing *how* it works and demonstration of the use
So... the two balls were "sucked" towards each other because the two balls created a small channel for air or water to pass, thus creating lower pressure compared surrounding space (atmospheric pressure). This lower pressure in this smaller channel creates a vaccum, pulling the balls together.
Kind of. The higher pressure on the outsides push the balls together. There's no "pulling".
Fantastic use of the word _thus._ 😄
A pressure difference in stead of a vacuum.
Yeah i think it's also due the the specific shape of the sphere.
it's not the vacuum that pulls the balls. You've said it: it's the atmospheric pressure that pushes them.
__
for a 3 cm radius sphere we get about 1 N:
P=f/A; f=PA = 101 Pa * 4Pir^2 =101*0.0113=~1 N
I'm a kindergarten teacher. Every Friday, we make a science toy. Other teachers in my school just say "Ok, let's make today's toy." I don't. In my class, we learn why it works, how it works. Ok, at kindergarten level, but it can be done. We have a toy each year that uses the Bernoulli principle of the ball in the cone. We use a plastic kitchen funnel and a straw, with a polystyrene (styrofoam) ball. I get the kids to color one half of the ball with a felt pen. That helps us to see how the ball moves. By watching the ball's movement, we can start to understand the airflow. That's when I link it to light bending around stars, or black holes. It's by looking at what you can see that you understand what you can't see.
In realms of air where wings take flight,
A dance of forces, pure and bright.
Bernoulli whispered secrets old,
In currents swift, a tale unfolds.
Above, below, a magic play,
In skies where dreams find their own way.
A symphony of pressure and speed,
A waltz unseen, the laws decreed.
As air flows, it weaves a song,
A melody where forces throng.
Upon the wings of birds in flight,
Bernoulli's dance, a graceful height.
At curves and bends, in fluid grace,
The air, a partner in this chase.
Velocity and pressure dance,
In every move, a sweet romance.
From wings that lift to planes that soar,
A principle forevermore.
In tubes, in winds, in rivers wide,
Bernoulli's truth, an endless guide.
A theorem sung in skies so blue,
In clouds and dreams, forever true.
A whispered secret, nature's rhyme,
Bernoulli's principle, through space and time.
I love this!! ❤
ChatGPT?
Me, using ChatGPT 😄@@bindum7178
This felt like something straight out of Ace Combat.
❤
Yes, very obviously ChatGPT
What a superb video lesson. Very clear and engaging. Many thanks.
😊
But WRONG.
The statements about Bernoulli's Principle are correct, but the demonstrations are very poor.
The balls, spoon and funnel age a result of the Coanda effect.
.
The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube.
..
To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface.
..
At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
This seems rather unintuitive, but you explained it very clearly. Thank you.
There is difference between watching an example with animation and watching one in real life. This one is faar better than anination.❤ Thanks!
You made my echocardiogram studies easier, thank you
What ? Hiwnplz
I mean how plz
Very simplified demonstration of the basic principle of Bernoulli .I wish some body could have explained me in my school level in such a lucid language.
Excellent demonstrations. best wishes for your channel growth
That's one of the educating channels you subscribe to.. once a fan of science always a fan of science
Clip này thực sự đã chạm đến trái tim mình. Bạn đã truyền tải những cảm xúc về tình yêu, lòng kiên nhẫn và sự bao dung một cách rất chân thành và tinh tế. Đây thực sự là một video có giá trị nhân văn cao mà mình tin rằng ai cũng nên xem để suy ngẫm về cuộc sống và cách đối xử với nhau.
This is counterintuitive. How did I live these whole years without knowing? How many more are out there that I think I know but I don't? Holy Castana!
I understand that Bernoulli's Principle exists, but I'm still trying to understand why it exists given the molecular nature of the fluid. The two things I'm trying to reconcile:
- The fluid when constricted moves faster, so there is a force (pressure) experienced by that fluid from the direction of flow.
- There can be fluids (e.g. the air in the bottle at 3:10) or objects (e.g. the ball at 0:42) external to the closed system that when they interact with this system they experience a lower pressure near the flowing fluid.
I may be able to come up with a molecular explanation* for other fluids adjacent to the flowing fluid experiencing a lower pressure (0:42) or even the two metal balls being pushed together (0:22), but the rubber ball experiencing lower pressure when it is directly in the flow direction of the fluid (3:10) is breaking my explanation.
*The intuition of the idea is to first start at an extreme: the fluid is moving so quickly that any other fluid that finds itself wandering into the pay is swept away. That said, I don't see how this intuition can be used to explain the rubber ball (3:10).
So many people who try to go to the molecule level make similar errors. The molecules are in thermal motions that are hypersonic! They are bouncing amongst each other at speeds FAR, FAR, FAR, FAR faster than any of this is happening. Those motions continue and there is only a drift that is added, vectorially to those motions. It all acts like a continuous medium. It is just the incessant pounding of the vibrating molecules that makes pressure on each other and surfaces.
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YES. The fluid is Accelerated away from the higher pressure - slower region, TOWARD the lower pressure - faster region. That flow, then HAS that very SAME lower internal pressure. . .
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It is the pressure difference, called a Pressure Gradient, that provides the Accelerating force on the fluid's mass.
Think of a brick with two, opposite-facing forces applied. If one is greater than the other, there is a net force and the brick will Accelerate toward the smaller force. RiGHT?
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That bricks Acceleration is NOT CAUSING that smaller force. . .
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Well, when there is a pressure difference between two locations, the higher pressure pushes more and accelerates air toward the lower pressure.
Euler is credited with figuring this out when he followed up on Bernoulli' work. According to John D. Anderson's Text on Fluid Dynamics, there is no indication in Bernoulli's notes that he understood the cause and effect. He only knew that the speed increase WAS ACCOMPANIED BY a pressure decrease.
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Bernoulli "happens" in a balloon that is venting to the atmosphere. Or your lungs when you blow.
The "high" pressure inside the balloon/lungs, push more than the atmospheric pressure outside the balloon/lungs.
That is a Pressure Gradient (in fluid dynamics terms).
The Higher potential energy inside is converted to the higher kinetic energy outside - where that "fast" jet of air IS AT the AMBIENT atmospheric pressure .
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THE JET IS NOT, NOT, NOT below atmospheric pressure. NOT BELOW!!!
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P.S. The Ball in the funnel is Coanda as the air curves around the ball, lowering the pressure where the funnel is nearest the ball, thus a lower pressure toward the smaller end of the funnel. Just about all the bad demos are due to Coanda causing pressure reduction, NOT the "fast" air. . .
Sigh. . .
.
The TWO balls is the SAME thing - Coanda. When air flows along a convex surface, the pressure near the surface decreases because of INERTIA. Air has mass. Fundamental property of mass is inertia.
Air traveling along ball surface is being held agains the surface by atmospheric pressure - LOTS of it!! As the surface curves away from the straight path, Inertia 'wants' to go straight and, in effect, "pulls away from the surface - INERTIA works against atmospheric pressure, therefore pushing less on the surface. See the video in my Blog. The Roller coaster analogy it 100% identical to flow along a convex surface.
This is SO frustrating with every one repeating this nonsense. . .
..
Here is my Blog that steps through all this physics correctly and the misconceptions.
. . BLOG:
*Understanding Bernoulli and Aerodynamic lift Correctly:* rxesywwbdscllwpn.quora.com
- -
Good luck and Happy new Year.
That was the best lecture I have ever seen.
Right on smarty pants, well explained and demos. Nice job!
The correct term is to say `Bernoulli's' Integral', since it is just an integral of the Euler's equations of motion for a particular case of steady, inviscid and potential flow. The term `principle' is related to something very fundamental, like The Principle of Least Action etc.
I honestly hope nobody is watching this video for Education purposes. Because my soul died in the first 2 minutes
That name is popularly known by people.
You can get the same equation by cancelling viscous terms and triple integrating Navier-Stokes' momentum equation. If I can do that, then it should be called the Navier-Stokes-Bernoulli equation, and it's not that
A name is just that, a name, so people can easily recognize the equation
An excellent learning aide. Very well done.
The pressure reduction is due to the expanding exit and not the narrow part of the system. The width of the entry may not be important but the exit, the wide exit creates a sudden increased volume hence the reduced pressure. I would like to see the same experiment be done without the expanding exit and see if there will be any differences
now this got my interest,
you explained it better sir 👌
The exit or diffuser has been measured (not estimated) countless times to have increase in pressure, the negative peak of pr3ssure coefficient is at most right before it, if your brainstorm was close to right the entire racing industry would be incorrect.
That happens at supersonic speeds
No, that is not Bernoulis principle. As she explained, the product of mass and velocity equal a constant, such that if you increase the velocity, pressure must decrease to maintain the same energy in the stream. It has nothing to do with what happens further downstream. You are confusing this with what happens when you pulse the pressure of a compressable gas, there are waves of low pressure radiating from the convergent and divergent sections. This is used in two stroke exhaust systems known as expansion chambers.
I would have loved to have seen this video as my younger self, it explains perfectly why airplane wings work
The first demonstration (with the 2 balls) perfectly explains porpoising in Formula 1.
Great demonstrations of Bernoulli's principle!
Venturi, excellent illustration.
Excellent presentation thanks a lot...beautiful presentation of the bit difficult concept to explain the students.....really....it is made too much easy......by you.....briliently simplified by demonsyrations and last photo of Actually venturimeter is also most important....Thanks a lot to All of you who have made Physics simple🙏
Fascinating video. However, I am not sure that the ball hanging in the water coming from a tap is really demonstrating the Bernoulli principle.
Firstly, the water is not being constrained to flow through a narrower channel - it is free to flow over the surface of the ball and so the cross section of the flow is probably not reduced.
Secondly, if you look at the flow of water coming off the bottom of the ball, it is deflected to the right after it has flowed over the surface of the ball. Changing the direction of the water flow to the right causes a reactive force on the ball towards the left, and this is probably what makes the ball appear to cling to the water - the ball comes to a rest where this leftward force is balanced by the rightward force of the downward water flow pushing on the ball.
I agree that the ball in the running water was not explained right or enough. But I think they meant that the change in the pressure of AIR around the running water causes the movement of the ball, not the pressure of the water. For some years now I have wanted to know why the spoon is pulled by the running water. And to me it looks like the curved shape plays the major role. I doesn't happen when you rinse a knife.
@@sylwiagotzman5422 Have a look at the video: Why are so many pilots wrong about Bernoulli’s Principle? by Fly with Magnar (ua-cam.com/video/uyRx25MSWng/v-deo.html). IMO he explains quite well what you're describing, it is the same as for an airfoil. Spoiler: it is also Bernoulli's Principle, and has indeed to do with acceleration of the fluid at the convex part of the spoon
It's the Coanda effect, not Bernoulli's Principle, that pulls the spheres or spoons together in a liquid or gas flow. The experiment would not be able to be replicated with cubes instead of spheres.
The amazing thing is, there were no electric blowers in Bernoulli's time, heck, there wasn't even electricity ! And heck, there wasn't even a faucet as we know it ! What a freaking genius mind is this, how did he figure out all of this ??
I think that this didn't explain the nature of the effect - the *behavior* of the particles (or strings) in flow relative to "stationary" ones.
A part two to the video, with particle animation, where you visualize the pressure exerted by particles which do not flow is very much needed in my opinion.
Great video, I now know how to work the spray bottles.😄😄
Unfortunately it is wrong. . .
.
This video is still WRONG. Please make corrections or remove it.
..
The statements about Bernoulli's Principle are correct, but the demonstrations are very poor.
The balls, spoon and funnel are a result of the Coanda effect.
.
The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube.
..
To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface.
..
At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
. . . .
This shows the proper way to measure static pressure within a flow:
Weltner Direct link: still valid on June 24 224:
“Misinterpretations of Bernoulli's Law
by Klaus Weltner, University of Frankfurt (G)”
FIG 3 Static Probe:
www.prirodopolis.hr/Bernoulli-Coanda%20Demo_files/Misinterpretations%20of%20Bernoullis%20Law.pdf
.
.
I have always had difficulty providing an intuitive explanation for this phenomenon, but if we try to think of pressure as potential energy rather than force per unit of surface area, perhaps the concept becomes a bit more intuitive. Or, imagine having a blown-up balloon. The balloon has a certain internal pressure. When the balloon is opened, the air inside the balloon starts to move faster. The internal pressure of the balloon then decreases because the potential energy of the air inside the balloon is converted into kinetic energy.
Good analogy
You have to embrace pressure to reach your full potential.
I was looking for a video to watch so I could fall asleep. Now I need not sleep but answer.
This is the benefit of educational videos ))
This just blew my mind.
I just wish someone would taught me like this when i was young.. when UA-cam was not that much a big hit and we had to pay exorbitant prices for just 1GB of internet data in India at that point of time we had to imagine all we could.. but now seeing this animated video with real life examples is what giving me an epiphany that what i imagined at that point of time was correct…
The seemingly stationary yet the active atmosphere around the two-ball system pushes the ball to come together when the air in between them is displaced. Though the atmosphere tries to fill in the gap again with air, the continuous removal of air makes the balls stick together and the direction of the displacing pressure dictates the direction of the balls' rotation.
👑for you my unsung hero
I had to subscribe! Amazing video!
Beautiful video. What a cozy nice accent. I loved it.
This is amazing! Thank you
You just made a carburetor.
Damb it you beat me to it lmao
And an air brush.
I thought it was a bong. But I ain’t that smart. 😂
Merge collector 😎
Syphon hose
By slowly pressing a box internal pressure would rise and the walls of box would heat up. Box would remain pressed in position that force heat of walls and heat of walls would be collected for electric energy production or for heating , keeping the box in pressed position would be done whit some closed brackets so no input of energy for keeping the box pressed so all its heat would be used to produce output of energy
An Air brush functions by a certain velocity of air passing laterally down a tube of said diameter - at a mid point down the tube is a T- piece with a pipe leading to a semi liquid media /paint source -
A pressure is formed at the pipe perpendicular to the main pipe due to currents being generated by the air flowing through the lateral pipe.
The flow of current in turn causes a vacuum at the pipe perpendicular to it. - With a carburettor this is called down-draft.
Its basically a pressure created by many things travelling at speed - Aircraft, Cars, Speed Boats - - If you have wondered why if you leave your tail gate open you get chocked by exhaust fumes being sucked back into the car.
Finally a good explanation of Bernoulli's principle
I love this woman's voice.
Oh! So for the thing at 3:00 it doesn't matter if it's an airblower or a vacuum, since it's symmetrical anyway, which can more intuitively explain why it sucks up the liquid
I really LOVE this video
Back in the 80s we had Bernoulli Boxes
These were large (for the time) memory disks using the Bernoulli principle
I know you have a large queue of ideas, but could you please put a video talking about this video along with one explaining the Bernoulli Box?
that's hilarous
Great video
You made my day with this
Glad you enjoyed it
Pressure and Flow = volume per minute - Just like voltage and current = watts. The amount of output remains the same even though you are changing the ratio of pressure to flow.
Very nicely explained basics.
Dolores Umbridge ?
Randomly stumbled to this video and thankfully I clicked it. Now I understand how the soap get used when my father use the his pressure washer with bottle of soap on the water gun.
This demonstration also covers the Coande and Magnus effects, maybe even the Casimir effect.
I'm waiting. Not forever. That's the message.
2:17 How'd you guys manage to get professor dr. cillian murphy?
The video is great and makes it clear how the pressure works for air and liquids and such, but how would the joined trumpet shapes react to sound. If one half is similar to the old ear trumpets that increased the sound, is this saying that the increase in sound is similar to the speed pf water, and that the increase in sound is matched by a decrease in some other quality of sound.
conservation of energy is a weak explanation because it does not explain why the fluid accelerated into the narrow section. Fluid has mass and a force is required to Accelerate a mass, so what is the force and what is the source of the force?
Your test tube is after the smallest opening, so the pressure is decreasing. The pressure increases to the maximum AT the smallest opening. It increases, then decreases suddenly like a divergent rocket nozzle trading pressure for flow/thrust. Like a transformer trading voltage and current with the power being the same except for the small loss of the transformer.
This is great!
This video is WRONG.
The statements about Bernoulli's Principle are correct, but the demonstrations are very poor.
The balls, spoon and funnel age a result of the Coanda effect.
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The tube inserted into the wall of the neck is protruding into the flow (seen at time 2:57) This causes the air to curve around the end and sides of the tube. This curved flow is the cause of the lowered pressure. This will work with no pipe around it; just the air blowing across the vertical tube.
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To correctly measure the static pressure inside your narrow neck, the end of hat tube MUST be flush with the inside surface.
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At time 4:51 we see that the two pressure sensing tubes appear to be more like flush, but it is difficult to see clearly. For that to truly sense the static pressures, there must be NOTHING protruding into and disturbing the flow.
loved it man
Nice explanation. But.... Swiss? Daniel was born in the Netherlands, famous university city of Groningen.
I love unintuitive tangible results in physics . It’s humbling that reality is not what it seems
2:30 try turning it around tho’. The air must have lower pressure than outside the tube…but the straw will experience +ve pressure because it is upwind of the narrowest part.
What about the pressure at the point where it starts its path to being a smaller diameter. Wouldn’t the pressure be higher at that point. I get the draw and vacuum at the end of the smaller diameter back to large but the pressure must increase at the direction of the flow where it’s going from larger to smaller. The pressure has to increase.
thanks a lot, the physics is wonderful
Just studied it for the first time, then found this video.
Cool!
The main thing to remember why this works is cause pressure moves from high to low and the fluids follow this direction of motion
Silindir içine direct injection teknolojisi geliştirilmeden önceki otomobillerin karbüratörü bu prensiple çalışmaktaydı.
And that demonstrates perfectly how a carburettor works in a petrol engine.
1:57 omg that makes so much sense
😂😂😂
what I think of this is that when air is blown very fast at sudden high speeds, pressure over there decreases because you just removed a given volume of air from that part. The speed at which this is happening, causes air, fluid or any solid to get attracted towards that part of the empty space due to partial vacuum. As we know, fluid will always try to fill empty space. In that case, since fluid from the surrounding area is trying to fill that empty space, solids surrounded by that part of fluid is pushed into it(given the solid isn't heavier than the force exerted due to pressure of the fluid) and hence we get this. In the same way, the volume of air flowing between 2 planes when they are near(due to the 2 engines next to each other) being pushed backwards is so high, that it creates partial vacuum between them and a slow attraction force(or u can say force due to fluid[air] at a higher pressure) surrounding the planes pushes them while trying to flow into the temporary partial volume of emptiness. I hope this explanation helps anyone who wants to understand this principle or visualize it.
Flow is displacing molecules between. Thus, flow displaced by volume pushes molecules.
When moving at considerable speed, this principle becomes tactile; breathing with wind-force against ones face 'should' make inhalation easier by intuition; however it is not the case, the faster the wind approaching ones face the harder it is to inhale, in-fact the lungs volume is wrenched from ones throat instead, and only an eddy-of air-pressure will allow ones respiration at-speed.
It's not true that faster air flow implies lower air pressure. Bernoulli's Principle only says that a faster section of flow within the same fluid flow must have lower pressure than a slower section within that same flow. If you stick your head out of a fast moving car and face forward, it should be easy to inhale.
"the lungs volume is wrenched from ones throat"
Maybe the wind was pressing against your chest too and that forced the air out of your mouth.
This is how a carburetor works.
Waah this is amazing
I dont believe this proves the air pressure in the main tube gets lower .the apparent suction is possibly caused by the airflow across the end of the little pipe inserted.
in the same way wind draws smoke up a chimney.
The weight and velocity and friction of the moving air in the big constricted tube causes this.
Another way to test the hypothesis is to blow air through a soft plastic tube with a constriction and see if the constriction expands or closes.
A very soft tube of thin plastic would probably ripple vacilating between open and closed is my guess.
For those who don't know physics, the world is full of magic ))
That is not a "paradox" nor "counterintuitive". That is a quite simple relation emerged from energy conservation principle... If you're struggling with these, perhaps you got confused over the "pressure" term - when velocity increases, the STATIC pressure is the one that decreases.
You nailed it. NOW it makes sense to me! Thank you!
Good channel needs more subs.
Is this the queen teaching physics
Great video! Peace out
Do you know the auto stop mechanism of gas pump to prevent spill over is based on Bernoulli's principle?
Hello. This is partially miss informative !
The Bernoulli theorem is challenging, but it kind of makes sense in a CLOSED system. You could think of it in lines of that you have roller coaster carts attached with springs. As they start rolling downhill the speed increases and the cart in front is pulling the spring to the next cart and vice versa. When they are slowing down uphill ... the springs compress (higher pressure) when the speed decreases.
Now when you start blowing stuff in to the surrounding atmosphere it gets messy. The two spears getting drawn together, it is because of the coanda effect. The pointed jet sucks the surrounding air with it and creates a low pressure. NOT to do with Bernoullis principle. I know; It is complicated :). The ball hanging under the water flow, counter intuitive or not has to do with the coanda effect, i.e. water being sticky and curving around the ball, hens creating an opposite force to the curving acceleration.
Oh well. Always have doubt, if your intuition says that something is not necessary so ;) .
You are right.
Finally someone pointed it out! There are so many misinterpretation regarding Bernoulli's Principle. It has rather strict assumptions for the fluid and the system (closed system, inviscid, incompressible, irrotational, no external force other than gravity etc.) and is not what people think it is.
Another wide spread rumor is that lifting force of a plane can be explained by Bernoulli's Principle. It is so wrong that NASA specifically wrote an article titled "Incorrect Lift Theory" for it:
www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/wrong1.html
Most videos claiming to be showing Bernoulli's Principle are NOT doing it under correct assumptions. Sigh.
Thank you for your effort, but you're assuming the surface is (or that it even could) pulling the air towards itself which is blatantly false, Coanda is a mere observation that air tends to follow the surfaces which is false as soon as flow separates, and it works on water because 1- surface tension and 2- water is much denser than air.
All aerodynamics forces are pressure driven, like Newton on fluids, which is the correct way of visualising it.
@@davidaugustofc2574, the Coanda effect also occurs with air (not just water) flowing over a curved surface, and is the reason for the spheres being pulled together with air flowing in between and for the sphere being pulled into the water flow. The same result does not occur if you use cubes instead of spheres. Those experiments do not exemplify Bernoulli's Principle, which applies to a single fluid flow. It is the pressure difference that causes the velocity difference, not the other way around.
@@mattcarter1797 My problem with the Coanda effect is that it is a gross oversimplification of the entire thing. You need to understand a little bit from several topics to understand what it really means, and those topics are more helpful than the conclusion.
Air is mostly neutrally charged, as gas molecules usually are, so the external electron layers will repel each other, a gas would expand to Infinity if it had a chance and enough time. However, due to the local, gravitational effects from the Earth, the air is squeezed together, and the balance of those is the atmospheric (sometimes known as static) pressure.
Gravity makes it so that pressure is very even for the same height all across the globe (temperature changes aside), so when a moving body is going through air and changing the pressure around itself, there will be a restoring force acting on the fluid to bring the new pressure value back to the original one. That is pressure will flow from high to low until there's negligible difference between the areas.
When the air gets close the surface it's pushed away by the first layer, that's attached to the surface due to friction, and when the surface curves away from the direction of flow it forms low pressure pockets that will exert less force on the surface and nearby molecules that the air surrounding it, thus guiding the air towards the surface. (Greatly helps if you have a way of visualising it)
And that's very simplified in it's own rights, since vorticity is a humongous topic on it's own, that I haven't even touched. I cannot understand how we're helping people by telling them about the Coanda effect and not the reasons behind it, you can't really learn anything from it. Okay, it was a great discovery for their time, but we're now at a stage where computers can generate airfoils from a set of requirements, we need to point out that air tends to follow surfaces and move on to deeper topics and not keep hanging on to it as explanation for anything.
Though visually captivating, the sheer volume and complexity of Bernoulli's formulae render memorization a tedious process.
No, i would not think that the air would push the spheres apart. I was thinking it may push them away.
5:20 Isnt then the amount of gas the travels through the pipeline limited by that section?
Its confusing. I think no, as the gas can be pressed through. Doesn't this then create a temperature difference, where the thinner part gets warmer and after it its colder than average?
And thats how maby not best, but most simple, and most reliable air pomp is made. Industrial usage of it is huge
As the speed of the air increases the ball redirecting the air has a boundary layer that causes the air to follow the curved surface . Air has weight . The air is acting under the laws of Centrifugal force as it is held to the ball by the low pressure boundary layer and causes what we call lift. Air accelerated across a curved surface "wing" creates lift by the weight of the centrifugal force directly relative to the speed . The faster the wing through that air the faster the air has to move to follow the wings surface which creates centrifugal force by kinetic energy. A wing flying just above VSO can not be over stressed . But above VNO can be overstressed easily . More airspeed across the wing more centrifugal force the air creates on the boundary layer. Such an experiment if I remember correctly was conducted on an F16 wing with a porous top wing surface where more vacuum was introduced I would suppose to slow the stall break. Boundary layers lifts NOTHING . It is the area between the wings surface and the fluid movement of air which can not do anything above VSO but adhere to the upper wing surface curvature creating a vacuum across the wing . The blunt nose of the wing along with angle of incidence only accelerares that air. The Whittman wing for the Tail wind has a thin wing with a sharp leading edge thus high take off , stall and flying speed. Ultralights use a very rounded leading edge to compress the air flow across the wing this a low stall speed .
👉 3:00 This principle solves the problems of empty nose 👃 syndrome, allowing the paranasal sinuses to be emptied and the viscous secretions of the middle and upper meatus to be cleaned, improving nasal physiology and breathing. Maintaining internal humidity in the Oropharynx.
Can u elaborate
Hi!@@selsabil3154
What are you referring to? What do you want to be prepared? Please be more explicit. I don't understand what you mean.
Then how come when I make the hose exit narrower the water shoots further and has more force
Bernoulli explained this a long time ago.
If an incompressible fluid flows out, then the flow velocity and pressure are related by the relation:
p+ro*v^2/2 = const (constant)
The conclusion is simple: the more the hose is pinched, the farther the jet flies.
A Venturi. Used in some priming pumps.
V2 is smaller than v1
No it's not ..
As, A1V1 = A2V2
Here A2V1
Please look at frame which is shawn at 1.48 minutes,
V1 < V2 it’s the same that V2 > V1, both means that the V2 is higher than V1
Yeah
Did you look that frame?
But isn't it more like the pressure of the fluid of the restricted section increases, while the pressure exerted by the fluid on its containment decreases?
If you observe this principle in water coming out of a pressure washer, then the smaller and tighter stream exerts more force on any object it encounters. The pressure within the restricted stream of water is higher and it creates a low pressure boundary of air surrounding it.
No, Chris. Your simplified thinking has led you astray.
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As the fluid flows TOWARD the inward sloping wall sections, the flow is TOWARD those walls and, therefore pushing more on them. It is similar to a wind that pushes more as it tries to approach a surface or blow you down.
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Then, a fundamental fact of fluids is that pressure at any given point pushes outward in ALL directions.
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That pressure against the wall is also eithin the fluid and it 'communicates' both inward and backwards, upstream and increases the pressure in the FAT section on the left.
>>The reduction in diameter CAUSES the UP-STREAM pressure to increase.!.