View Full Version : Straws in Space

Hat Monster
2002-Apr-20, 04:42 AM
Page 256 states "you can see the liquid in his straw go back down after he finishes sipping. Since there is no gravity on the shuttle, the liquid would stay drawn up the straw"

Capilliary action comes into it too. This may actually draw the liquid down anyway. Anybody know for sure?

2002-Apr-20, 10:09 AM
This has actually been discussed at the IMBd site, as part of their 'bloopers' section. My guess is, if it's a carton with drink in, it must have some sort of bladder inside to stop the liquid floating around. If it was left to float around, every so often, a loud rude noise would occur as air got sucked up the straw. This bladder would have to be squeezed by air inside the carton, as the liquid went up the straw. That would mean some vent of some sort would be needed in the box to allow the air in. I suggest that this vent would be calibrated to allow enough air in to allow the liquid to be drunk, but would shut off just short of pressure equalization, to draw the liquid back down into the carton, thus saving having to mop up floating droplets of orange juice etc.

I have way too much time on my hands.

Donnie B.
2002-Apr-20, 12:00 PM
It's pretty easy to rationalize this "error" -- far more so than the billowing dust on the Moon, or the drifting stars in the Discovery sequences.

Consider: the shuttle in question was a commercial passenger spacecraft. Its food service was intended for ordinary citizens, not professional astronauts. Therefore, the food service items would be designed to limit "oopses" like having globs of strained peas or orange juice floating around the cabin.

I envision the design something like this: the food or beverage is in a flexible plastic bladder (which may in turn be contained in outer packaging). When you suck on the straw, the bladder deforms and collapses. When you remove your mouth, the bladder material has enough "memory" to try to expand to its original shape; this draws the food in the straw back into the bladder, preventing it from leaking out the end of the straw.

Having a bit of air in your next sip is a lot less of a problem than having gloop floating all over the place!

2002-Apr-21, 12:12 AM
For what it's worth, capillary action would draw the liquid *up* the straw... But since the straw is of a fairly large diameter, the capillary force would be very small.

(It's wonderful fun: if you put a small enough pipette into water, you can actually get a momentary jet of water into the air!)