You have a glass jar. You pour in water with a pitcher until it is half filled. You then seal the jar with an air-tight lid. (The only other thing in the jar is regular air). Assuming that the water in the jar is not already boiling after attaching the air-tight lid, how do you make the water boil?

boiling: the state in which liquid water is rapidly changing to water vapor (ie, the water is accually bubbling, not just steaming)

For clarification, the water is plain distilled H20. It is not heavy water, water with impurities, etc...

You cannot transfer or use anything that transfers light, heat, magnetic, electric, or chemical energy into the jar. (and no, shaking the jar till the water friction causes the water to boil does not work)

You cannot open or break the glass jar.

The area in the jar cannot increase or decrease. (You can try but the jar will not shrink, grow, or deform in any way)

You cannot insert anything into the water.

You must be able to conduct this experiment with easily attainable equipment, chemicals, and other materials. (ie, no radioactive chemicals, no superpowers, no multi-million dollar scientific equipment, you get my drift...)

(Note: although it is hard for it to succeed, you can conduct this experiment at home and get the water to boil without any special equipment.)

During Christmas Eve my brother and I discussed this problem and agreed to the following test.

If boiling water is poured in a glass bottle and then it is closed, the pressure inside the bottle will raise and the boiling temperature will also raise.  Because the water is no longer heated, the boiling will stop.
Putting ice on  the bottle will cool down the bottle and then cool the air (and the water).  Here's the problem, the heat transfer coefficient from water is three orders of magnitude greater then that from air. Glass is inbetween.
Taking this into account, we said that the water level in the bottle should be much lower then the part of the bottle that would be covered by the ice.

And the test: safety glasses on (I wasn't very sure about the safety aspects), water in the bottle, I closed the bottle and almost immediately, it stopped boiling.  Then nothing happened until +/- 1 beer later, slowly, bubbles started raising to the surface, not a lot, not heavy boiling, nothing spectacular, but definitive boiling.

Posted by Hugo on 2005-12-26 09:59:00