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Theochem bit the big one again. Since I had serendipitously moved everything over to Scienide last night, things should still be okay on this end. (Although I still have to get the counter working again.) That shouldn't take too long, but it's annoying that Theochem's been so flaky recently. I had hoped that it would be reliable for years to come (so it could host this page!). Oh yeah, theochem.uwaterloo.ca points over to scienide.uwaterloo.ca so you don't have to worry about changing your links just yet. Besides, this may just be a temporary measure.
While I'm here, there's another little physics problem in Science Teasers you may be interested in:
Weightless Water:
A corked bottle, half full of water and half full of air, is about to be sent into space in a satellite. When the water becomes weightless, will it be above, below, or in the middle of the air inside the bottle? Or will it cling to the glass?
I didn't get the answer to this one, nor did weirDo. Can you?
Thursday, May 11, 2000 at 15:37:30 (UTC)
Hwan's still not entirely convinced about this one, but...
The water will cling to the sides!
After reaching orbit, the weightless water will have only one force acting on it, "surface tension", which is the cohesion of the water to itself and atoms that come into contact with it. Since it was in contact with the "bottom" of the bottle to start with, the weightless water will "crawl" up the sides of the bottle, in the same way you see on the meniscus of a test tube. Only difference is that on Earth, gravity thwarts that climb (not completely..thus the convex meniscus)
of course, this is the steady-state answer...after the sloshing has died down!
Reg<e-mail>
Thursday, May 11, 2000 at 15:44:49 (UTC)
I'm thinking it should form a spheroid in the middle of the bottle.
Doesn't surface tension work to pull the liquid in to a ball, which would maximize the surface, rather than minimize it (or lower it, in the case of it wrapping along the walls)? I'm fairly certain of this.
Dr. Hwanalytic
Thursday, May 11, 2000 at 15:50:03 (UTC)
Of course, the Dr. means MINIMIZE the surface.
Mr. Typo
Thursday, May 11, 2000 at 15:51:59 (UTC)
The surface area of the spheroid may or may not be larger than the interior surface of the bottle, given a certain total volume of water. Depends on the bottle!
the reason water usually forms a sphere in weightlessness is because of the surface tension I mentioned; in this special circumstance, things have conspired so that it's more likely the water will stick to the glass than to itself.
Hwan, don't you remember doing this very experiment from the roof of the Great Hall in Village!?
Reg<e-mail>
Thursday, May 11, 2000 at 16:22:16 (UTC)
There will be three stages:
First, the water will fly up to the cork, upon which it will desperately throw its "weight" to try to escape home. Much splashing at this stage.
Secondly, the water will give up, entirely exhausted and depressed, as far from the source of its failed doorway to freedom.
Finally, the water will etch its memoirs along the inside of the glass, and lay to rest in the new made scratches to pass away peacefully at last.
girl
Thursday, May 11, 2000 at 20:13:46 (UTC)
Well, I was going to agree with Hwan, but that seems a terribly boring answer after reading what girl had to say...
Was the maple syrup cloudy?
Mister Man Mikeo
Thursday, May 11, 2000 at 21:17:01 (UTC)
I've thought about this some more, and I'm more and more convinced of my answer.
Think of water droplets on a car.. they bead up, trying to clump and NOT spread out on the surface of the car.
Unfortunately, I'm not sure that the surface tension is strong enough to make the water shy away from the interior of the bottle. My hunch is that it is though.
Anyway, for the water to climb over the insides of the bottle seems extremely counter-intuitive.. it seems to imply that when a liquid spheroid in a space shuttle touches a wall, it will try to spread itself along the wall.. which doesn't sound right at all!
Of course, the only real way to do this is to actually try it. Hurry and tell us, QYV!!
Dr. Hwanalytic
Monday, July 12, 2010 at 21:24:31 (UTC)
While the answer to this brain teaser has long since been discussed (and proven), I was reminded of it again when coming across this:
Astronaut demos drinking coffee in space
http://www.youtube.com/watch?v=pk7LcugO3zg
Hwan