Angular Momentum Demo: Spinning Bottle
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- Опубліковано 21 жов 2024
- In this demonstration, water that is originally at the bottom of a bottle splits when the bottle is rotated, with some of the water going to the top of the bottle and some remaining at the bottom. This split increases the moment of inertia of the system and decreases the angular velocity to conserve angular momentum.
Man I love physics professors. It might not be the case everywhere but it seems university physics professors are just cool flipping dudes. Like damn.
From my experience, yes
Your absolutely right !
My HS physics teacher gave up on my class...
10:12 PM
4/8/2021
Yes
they love what they do
Until they give you a ship load of homework that asks you to derive equations that has never been taught during class and use up 5 hours just to look online to find that there are no examples and answers so you look for research papers to find extensive amounts of complex equations and learn everything out of syllabus and write three pages of explanation using all the theories you learnt just for them to give a zero for your work and give an answer that is so simple, it absolutely contradicts on what you learn and when you ask them, they tell you that you think too much. They never tell you how to simplify how you think and give you an answer that you think is logical and when you take the exam, it is always something new and you have never tackled such a question before.
Sorry, I'm still pissed that physics is the sole subject that tanked my GPA.
These little demonstrations are easy way to understand how angular momentum and inertia works, great explaining!
I learned of this effect from my Gramma in the 1960's, but did not know the scientific name until much later. She showed me how to detect whether an egg is boiled or not. A boiled egg will spin fast on a table top, while a raw egg will only spin sluggishly one or two revolutions.
The way I detect if an egg is boiled or raw is to hit it with a mallet.
The video is showing how the changing moment of inertia changes the speed of rotation. I think what you are describing just has to do with the way a "solid" boiled egg or a "liquid" uncoocked egg reacts to the shell being spun. The inside of the uncooked egg slips and doesn't start spinning very much after a quick flick.
@@albertbatfinder5240 Or eat it maybe ?
@@Alex-lc1bv nope when the uncooked egg spins the liquid spreads thus increasing the moment of inertia
another way to see if the egg is boiled is to spin the egg and then stop it with a tap and if it stops it is boiled but if it starts spinning again is raw. This is because if it is raw some of the angular momentum of the shell is given to the egg white and when you stop the shell the egg white keeps spining and gives some of the angular momentum it has to the shell again and makes it rotate again while the boiled egg is solid so when you stop it the egg white stops too
he really is catching it well while looking at the camera.
SO epic
Fun fact is that you are from India.
@@HarpreetSingh-mf9qj yes i am an indian
@@HarpreetSingh-mf9qj IDGAF
Well, if you know where something is, you don't need your eyes to catch it. I though this was obvious.
Honestly just saying "kids play this game called flip the bottle" was the best move to stop this trend
This the way to get connected with Physics!
With simple and everyday things!
Yes and unfortunately there are very few people who relate physics with the application in their daily life!
and i just thought how no supercomputer can EXACTLY predict trajectory of that bottle because of fluid mechanics happening there...and that's not simple....
1:08 "we're gonna water these plants with.."
The blood of your enemies, Professor? c:
"This water with red food coloring"
Oh, ok. That works too.
4 years later and I think this video is gonna hit the UA-cam algorithm
You weren't wrong
If you are here, then it means its already been hit.
@@senkodan p
*His grandson playing “flip the bottle” with his friends*
Him: Hmmm, Interesting 🤨🧐
Physicists are known for their ability to be enthralled by their surrounding physical world - this man is one of them.😁
@@organicfarm5524 true. I just see these types of behaviour in them and think, “Why the hell didn’t I think about it?”. Truly wonderful.😄😊
His brain: L=rxp
Lies! This man has never had sex.
Scientists, like artists, see beauty in the world everywhere. Unlike artists, instead of grabbing a paintbrush, they go get a calculator.
Except that he did not grab a calculator.
As an artist (painting mainly) who became a physicist: I now enjoy creating visual representations of equations or just statistical relations using python. Sometimes using c++ when my work gives me something to play with.
Somehow it's just as enjoyable, but a lot more private an enjoyment
@@widmermt they grab a soft chalk and a clean board. ( Or some pencil and paper)
@@threetunes7810 Well that seems pretty interesting!
@@informationparadox387 Yes. That is
This video got all this attention within the last week. Great video.
I've noticed this same phenomenon, but never really gave the reason much thought. Makes a lot of sense, thanks!
Had he landed the bottle perfectly, would have been even better ending
It's very clear! The water remains in the bottle...Amazing!
Best supporting actor to the plane apparently flying donuts around the area.
I was waiting for him to do bottle flip at the end xD
A nice demo for conservation of angular momentum. Thank you.
Fantastic hand-eye coordination
Great physics demos in this channel!
"Dylan, what's that glass tube thing with the picture of Tommy Chong on the side, that you kids are passing around?"
""Oh. Uh, hi Grandpa. We're playing 'Flip-the-Bottle' "
"Hey, great! Let me show you a little about angular momentum"
Science students are also good at sports. I mean just look at him how professionally he is catching the bottle 👍👍
This looks really great, as I high school student it feels amazing to see it
Cool, now that you explain it I can see what's happening. Neat, thank you!
I used to be so curious about these things and one of the best thing I can tell is if you want to rotate half or 1/4 th filled bottle with same as fulfilled then you have to push bottles cap side downward while throwing bottle up try it and tell
Exelent but why not flip it landing at the end?...
Wonderful demonstration
... in slight disagreement.
As water splits in the second case so axis of rotation is roughly same as in the first case. Moment of inertia is more in the first case than the second case: so rotational speed should be more in the second case. But it is not !!! It has to do with inertia of rotation of water as in the case rotating "rotation of boiled egg and the rotation of raw egg".
But why is the water dividing in the first place? All it had to do to conserve the angular momentum is to rotate as fast as he made it to do. So why does the water take the detour of dividing to slow down the rotation to conserve angular momentum when it could just turn faster? I think centrifugal forces play a role here, too, right?
The initial force, and movement isnt strong enought to move the water to the bottom of the bottle. this is from anécdotal evidence.
The water tried to stay where is was but the bottle moved in relation to it.
@@alphalunamare But it divided. So some of the water moved regardless what the bottle did.
@@LGlink-rz2xc That's the effect of friction twixt the water and the plastic inside which is hardly smooth. Probably a more fizzy water would ride the micro surface of the plastic better?
Water does not have tensile strength. Any rotation of a water body causes it to spread out until it meets a mechanical limitation, due to centrifugal force like you said / inertia for physics pedants. Because the bottle is long, the most spread out configuration it can obtain is 2 roughly equal halves at each end, so that's what happens.
When I flip my dog's Ferminator, it not only flips but also rotates. I start the flip with the bristles facing down and when I catch it the bristles are facing up. Explain that, Mr. Professor.
Wonderful video teaching on basic physics principles! Thank you.
I remember this professor from another video, damn he's good.
I wish we were taught in a similar way
Go watch more of his lectures and you will be
He is a good catcher. That's what I am able to understand.
A gyroscope is still the best device for the demonstration IMO.
What’s your top 5?
IMO means
@@manjunath7497 in my opinion
Maybe a better device for the physics, but this is the best physics for the device of the bottle :)
@@UnfamiliarPlace Agreed in this regard! Education is about conveying ideas and understanding using whatever is available IMO :)
I don't know why UA-cam suggested that I watch this, but I'm happy (and hopefully smarter now) that I did.
Goddamnit the thumbnail preview looped in such a way that I thought it reverses the flip mid air.
Why the shadow cast by the water on the column is black when bottle is far away and slightly turns pink when near
Great video thank you so much for this!
The moment of inertia of the split water bottle is still quite a lot smaller than the full bottle. So you haven’t really explained why you can’t flip it as quickly as the full bottle, which you don’t seem to be able to. Why start of with a full bottle for the explanation?
Almost at the end you can see some of the water STAYS in the bottom while rotating...why is that?
I realized that this would be used for perfecting the bottle flip technique
I'm so glad that I watched this video.
What if the air in the bottle is replaced with a gas like hexafluoride? Helium?
But what causes the mass to split within the bottle? If it starts the spin at the bottom, why doesn’t it stay there with centrifical motion?
Sir you are a legend.
Strictly speaking, moments of inertia are defined for *rigid bodies* ... not composite bodies with deformable media.
Is this the action Lab's father? Cause they sound totally alike.
Action Lab guy has a annoying voice, talks through his nose.
It could very well be a regional dialect, the pausing matches so well
Hahaha yup
Thanks for this and your other videos - isn't it odd how we physicists see physics everywhere!
But how to spin it fast...pls reply
I had this doubt.
Case 1: Bottle completely filled.
Case 2: Bottle 1/3rd filled.
The energy provided by the hand in both cases is approximately equal.
If we do a simple energy balance:
Energy provided = Potnetial Energy(PE) + Translation Kinetic Energy (TKE) + Rotational Kinetic Energy (RKE)
In both cases approx 'energy provided' is equal by the hand. PE and TKE would be less in case 2 as mass is less. This means that RKE-2 (RKE for case 2) is more than RKE-1.
RKE = (Moment of Inertia * Angular velocity)/2 {MOI*AV/2}
In case-2 even if water is getting divided into two, the moment of inertia for case-2 is less than that of case-1.
But RKE-2 > RKE-1 and MOI-1>MOI-2.
So considering all this together, the angular velocity for case-2 should come out to be more than case-1.
But that is not the case.
In case-2 there is relative motion of water wrt bottle, which means there is relative velocity of water wrt bottle. I feel the correct explanation would be that some part of the energy provided is converted to translation motion of water inside the bottle.
I am not sure although. Please let me know
I'm no physicist, just constructor but I think you omitted that energy provided by hand is larger for larger mass, to exert same velocity.
@@tgstudio85 Yes that is correct. More mass means more energy is required to attain the same velocity. But if the same energy is provided, the lesser mass will have more velocity, which is kind of my argument.
Brilliant explanation....
Really awesome
Did land the flip tho?
Everyone: Happy birthday to you!
Grandpa: Well that's interesting!
I discovered and figured it out on my own. Great minds think alike😆😆
The bottle gyrates, centrifugal forces split the water into two equal parts one at each end, and gyration slows.
Why did the water split?🤔
Maybe you find "Beyond Cutting Edge with Bob Lazar" interesting parts to popularize?
But why does the water split?
2:27 It's spinning about the axis passing through the cap of the bottle (not the liquid itself). Angular momentum isn't minimum in the case.
Bro, the axis about which it is rotating is passing through the cap only until the bottle is in the hand of the man. But as soon as the bottle leaves the contact with the hand (which was earlier acting as a hinge), it starts rotating about it's COM... in short, the axis of rotation shifts from the cap to the COM of liquid...
(Btw, are/were u preparing for NEET/Boards only?)
(Cuz any JEE aspirant would've understood this point earlier😅)
Mom can we have: water bottle challenge
Mom: we have it at home
It at home: flip the bottle
Interesting video
Everyone: trying to understand physics
Me: why the water is red???
0:52
Everyone: watching the bottle
Legends: watching the shadow
Thanks for the video! Looks like I have a great question to write for the next Physics test :D
Although I had not noticed it in my day-to-day activities, I suppose that the angular velocity of the universe must also be decreasing, as it expands.
That's a really good point. Got my brain thinking.
American teachers are amazing. We (mexicans) don't get this kind of examples at school.
Man you got some skills!!!
Wtf super explanation dude I got it at the end
Very informative
Water we dune heir b?
Amazing
"A game that children play." You think this is a game, bro? Bottle flipping is a blood sport for men.
is this for 5 year olds?
So he never explained what part of this is the angular momentum.
This efect causes the Water Bottle Challenge
Wonderful
Very cool!
He is a physicist, so he can flip the bottle at the exact same angular speed every time.
Same thing happens with a boiled egg vs a raw egg when you try to spin them the boiled one spins faster
"a game that *children* play"
and i took that personally
But he forgot to gave the flip with a dap at the end
Everybody should get a teacher like you.I would have became an Einstein 😴
I'm impressed he didn't drop the bottle
It seems interesting to learn physics in this way....
Hum. Wonder if this works with " Spin the bottle" game? lol
Im not sure why this would have to be explained. but i guess so.
very interesting....
One of the conclusion: Steel I-Section is Better Than Solid Steel Rectangular Section To Be Used in Beams
why are comments so recent
Try flipping a hammer and then hit the handle downwards as it spins. It’s not fluid but interesting. Thank you.
1:05 for my fallen homies
I think he is trying to explain mechanics of rigid bodies in motion with an example which can be better explained through newtonian fluid dynamics.
......you are tossing 1/4 the mass as well
flipping the bottle was 4 years ago holy molly
Jajaja amazing! Thanks teacher
Brawndo’s got what plants crave
Anyone else see the floating bottle in the thumbnail?
Just Wobbled off the shelf while trying to place back Carefully..
Peanut Butter Flavored Marlboros
what
Here's another for you to analyze... or not... somebody probably did: with a raw egg and with a hard boiled egg, which you are presented with, find which is which...
Lovely lovely lovely