Physics Holds the Key To Performing the Flipping Water Bottle Trick (arstechnica.com) 56
An anonymous reader shares a report: Think of how ice skaters extend their arms and legs to slow down rotation coming out of jumps or spins. It's the same principle: conservation of angular momentum. Once the bottle is set in motion, its angular momentum remains constant. But shifting how the mass inside (the water) is distributed increases the bottle's rotational inertia (how much force is required to start or keep it moving). This slows down the bottle's rotational speed. Physicists from the University of Twente in the Netherlands decided to analyze the underlying physics [of flipping a half-full bottle of water so it lands upright] more thoroughly in a series of rigorous experiments and develop a theoretical model. For the first version of the experiment, they used a partially filled water bottle. For the second version, they reduced the variables from the large number of water molecules in the bottle to just two tennis balls in a cylindrical container. In both cases, their measurements clearly showed the dramatic decrease of the container's rotational speed, resulting in a nearly vertical descent, so the bottle landed neatly and upright. Tracking the sloshing of the liquid and the changing positions of the tennis balls demonstrated the redistribution of mass, shifting the moment of inertia.
Next up on Slashdot (Score:5, Insightful)
Fidget Spinners: We review 10 the top ten fidget spinners of 2018!
Re: (Score:3)
Fidget Spinners: We review 10 the top ten fidget spinners of 2018!
<obligatory>
Number 7 will surprise you!
</obligatory>
Re: (Score:2)
Ummm ... yeah ... (Score:4, Insightful)
No shit, physics holds the key to pretty much everything. :-P
Re: (Score:2)
Re: (Score:3)
That Newton fellow didnt even invent anything, he just described what was already there. Why is this guy even famous? ;)
Because he also invented a tasty cookie with a fig filling.
Re: (Score:2)
Guns don't kill people! Physics kills people! - Dick Solomon, "Third Rock From the SUn".
Re: (Score:2)
I'm shocked, SHOCKED! To find that physics holds the key to describing physical phenomena.
Flipping water bottle (Score:1)
What is this water bottle trick, and why are they so triggered by it?
No shit (Score:3)
Was this from the "No Shit Department of Things That are Obvious"?
Re: (Score:1)
I hit the comments to write "no shit", but you beat me to it and put it far more eloquently than I could. Well done sir.
Cats and toast (Score:2)
Re: (Score:2)
Arrgh, and I lost all my mod points yesterday...
Physics is the key to physical feats. (Score:5, Funny)
You don't say! -_-
Re: (Score:2)
Ig Nobel Committee on line 2 (Score:2)
Physicists from the University of Twente in the Netherlands decided to analyze the underlying physics [of flipping a half-full bottle of water so it lands upright] more thoroughly in a series of rigorous experiments and develop a theoretical model.
I sense they are gunning for an Ig Nobel Prize [wikipedia.org] with this critical and ground breaking research.
Damn (Score:2)
Wish I had that kind of time... (Score:2)
And they are getting paid for it I assume.
If not, cool project.
If so, just another step towards Idiocracy (with regards to the research topics at the beginning of the movie).
Feh (Score:5, Funny)
Only General Flipping (Score:2)
The flipping water bottle trick only works for inertial frames of reference.
Actually, it doesn't. It requires a gravitational force to cause the bottle to land. Since a uniform gravitational field is indistinguishable from a frame undergoing constant acceleration the flipping water bottle requires an accelerating i.e. non-inertial frame to actually work. Hence there is no Special Flipping, only General Flipping.
Contrary opinion (Score:4, Interesting)
Well all of the Slashdot posters today seem to be gunning for most snide comment.
Maybe they didn't read the whole summary? Because I for one thought it was pretty cool they reduced the problem down to a canister and two tennis balls to demonstrate the same effect in an easier to understand way.
People may find this pointless. but you never know when understanding something others consider to be obvious or not worth knowing may be helpful. You never know what kid may get into science because of being fascinated by this reduction.
I say, good work!
Re:Contrary opinion (Score:4, Insightful)
I found the headline useful (Score:2)
Physics!
Who knew?
It's *physics*?!? (Score:2)
Really!? I thought all this time it was by magic! </sillyme>
I guess that explains this teacher's ability [youtube.com] to do so many flips then!
Obligatory Jurassic Park quote (Score:3)
"Your scientists were so preoccupied with whether or not they could, they didn’t stop to think if they should."
Re: (Score:2)
While this is kinda neat..... (Score:2)
Ahhh, millennial (Score:2)
This is what happens when millennials are old enough to go to university.