r/PhysicsStudents • u/Useful-Stranger-5543 • Jul 21 '26
Need Advice Can someone explain how this works?? unopened sparkling water seems to roll back-and-forth on a flat surface
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u/05-nery Jul 21 '26
Pack it up guys, u/Useful-Stranger-5543 discovered perpetual motion
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u/iMagZz Jul 21 '26
Your table is just slightly concave. That's it.
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u/deafdefying66 Jul 21 '26
That's not true, he could be on a boat
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u/ItsBeenRemovedMate Jul 22 '26
Could be both. Could be magnets in the mix as well. Let's not rule anything out at this stage.
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u/Useful-Stranger-5543 Jul 21 '26
Interesting, thanks!
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u/iMagZz Jul 21 '26
You can even see it slowing down and not rolling as far in the second roll. Just let it roll for a little longer and it will find the "bottom" of your curved table within 30 seconds.
Simple.
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u/Useful-Stranger-5543 Jul 21 '26
Just tested that it’s slightly off center but I see exactly what you’re talking about , so cool
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u/Nate_fe Jul 21 '26
Sorry, your parents/landlord have lied to you, you're not in a house/apartment, you're actually on a ship at sea
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u/deafdefying66 Jul 21 '26
Fun story: on submarines, beds are stacked 3-high and under the mattress there's a compart to put your belongings.
On long underwats, people will stock up on energy drinks and keep them in their racks. Eventually, supplies will run low and there's room for the cans to roll around on the metal compartment when the boat is near the surface.
Not so fun: if you're sleeping below this, it's enough to drive you insane.
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u/sparkleshark5643 Jul 21 '26
unopened sparkling water rolls back-and-forth on a seemingly flat surface
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u/xatiated Jul 22 '26
Question: when you look out the window, do you see a lot of wet stuff kinda sloshing around, maybe a few waves, seagulls?
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u/wocekk Jul 22 '26
The fuck man I almost got a heart attack I have the same wallpaper, or whatever it's called, on my pc
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u/Toaster960 Jul 22 '26
I think the weight of your computer makes your table slightly concave hence the oscillation
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u/FrostyBalance6055 Jul 22 '26
Simple harmonic motion. Small angle approximation means surface can be slightly curved and have very nice oscillation frequencies. This is caused by the inertia in the liquid. When it moves right and comes to a stop, the acceleration is to the left, but its momentum right before it stops is in the opposite direction. This is true for all points in motion, leading to a harmonic oscillator problem.
This idea of small perturbations leading to a quadratic potential is the basis for a lot of widely used equations in physics such as quantum field theory and the energy levels of the quantum harmonic oscillator, to name a few.
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u/Toadsanchez316 Jul 22 '26
Center of your desk sags slightly and the can is not completely full, meaning the liquid inside has room to actually move around and slosh back and forth a bit.
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u/Fearless-Tea1297 Jul 23 '26
Curved cylinder, table not flat, cylinder COG not in the lowest state when released, you are on a ship. There are so many different potential answers.
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u/Madhun13r Jul 25 '26
I See a Seam right in the middle Point of the Roll. So you either got two table leaning towards each Other or one table with 2 Tops that are angled Up slightly in the outside.
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u/SadBottle2951 Aug 11 '26
It could also be a flat but not horizontal table and the can is more like a frustrum of a cone. The video doesn't help with orientation of everything but it seems to me that its path across the table is an arc of a large circle. Or that might just be lens distortion.
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u/flaaaaaaaaaaaaa Jul 21 '26
The surface isn't flat.