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.)
(In reply to Just a guess
S4TD may be on to something here: you can't transfer heat into
the jar, but transfering heat OUT of the jar is not forbidden. I
think this is the answer.
So maybe fill the jar half full, heat in the microwave until boiling,
let it cool just enough to stop boiling, then add the lid, then dry ice
or regular ice on top of the lid.
Another way would be to make sure the jar is perfectly clean, and
microwave until the water is SUPERHEATED (not easy to do, but is
possible). Then add the lid and minimally shake the jar, which I
don't think violates the first bullet point.
Posted by Larry
on 2005-12-06 14:23:37