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.)

Seems there is some difference between boil and evaporate: if to consider the
question in Subject formally, I could suppose a "standard" way for fast
(few seconds) evaporation of water in physical research style:

                    ====
                     ||
       +---==========++==========---+
       | +-======================-+ |
       | |                      thermoinsulting tube  | |
   +---+ +--+                (with valve!)   +---+ +---+
   |             |                                |    |####### |     |
   |--o-o-o--|                                |~~| absorbent |~~|
   |--water--|                                |~~| #carbon# |~~|
   +---------+                                |~~+------------+~~|
                                                   |~~~ liquid N2 ~~~|
                                                  +----------------------+


So, it is possible to evaporate water with using liquid nitrogen --- the right
part of diagram is simplest fore-vacuum pump, absorbent carbon after contact
with low temperature (77K) of liquid nitrogen absorbs a lot of gas and if
volume of water is small, it can disapers during few seconds (the problem is
that evaporation can be too effective and water not only boil, it can freeze
at the same time, even if you use usual pump without any additional cooling
like in the picture

Posted by Wallace North on 2005-12-12 14:57:35