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 Perhaps there is no solution as stated? by Mindrod)

There is only one solution as stated.

There are only TWO ways to boil a liquid.  Raise temperature or lower pressure.

Since raising temperature is out of the question, lowering the pressure must be the key to this.

In a closed system, the only way to lower the pressure is to either add a vaccuum that is attached to it or... lower the temperature.

TECHNICALLY, as it is stated, there's nothing in the rules about REMOVING heat from the jar, but then again, how will cold water boil?

Also, waiting for a long while will make the water reach equillibrium with the air, so if the air inside the jar is saturated, the water will not boil.

Sooo, let me get this straight.  You cannot change temperature, or connect a vaccuum.  Therefore, the temperature and pressure will remain constant... unless the lid can be deformed.  And while you, MindRod, think that he meant the VOLUME of the jar, the key seems to be "(You can try but the jar will not shrink, grow, or deform in any way)".  Why would he say the JAR specifically?

So, I think he wants us to use something like a balloon as an airtight lid, and use a vaccuum cleaner or something to suck on the balloon, creating a vaccuum.  I'm guessing that the reason it will be difficult lies in the balloon breaking.

Posted by Alexis on 2005-12-07 16:07:13