What happens when you boil water, in space?

Article by: Hector Janse van Rensburg

Well, here on earth, when we boil water or indeed any liquid, the bubbles travel upward in a fairly regular pattern. But what would happen if you were to do the same experiment in outer space? Not only would this information be of interest to us, but it is also vital information aboard spacecrafts.

So, if the bubbles don't go up, because they have no buoyancy, what do they do?

In order to understand this, we must first take a look at how boiling works.

When a liquid heats up, gravity causes the hotter liquid to rise to the top and the cooler, denser liquids will fall the the bottom. This is called Convection and cannot take place where there is no gravity.

The fact that the hotter liquid doesn't rise up, means that the water will also boil much more quickly, because the hot liquid stays where it is, unlike here on earth. This means the liquid up the top will stay cooler.

It is now that the bubbles of steam start to rise, and the question is asked once more. Where does it go? The answer is simple, it stays in the centre of the liquid.

Ok, so now we know where it goes, but how can we solve this, and get that bubble out of there?

When the bubble stays there, it will act as an insulator and therefore water will not be heated, so to stop this, turn the container on it's side, heat the sides rather than the bottom, and spin it whilst it boils. This means that the bubble will travel to the centre as the water spins and the water is heated from the outside, then you should insert a tube through the middle of it, and suck the bubbles out.

Here is a diagram for clarification :

To watch a video of water boiling in outer space visit this link.

http://science.nasa.gov/headlines/images/boiling/poolboiling_web1.mov

About The Author: Nickname Hecky, new to writing articles, and thought I\'d give this a second go.