Boil water in paper bag

From ScoutHelp

This always seems to amaze people!

Simply take a paper bag, fill it full of water and place it near some hot coals.

The top of the bag will burn where the water is not touching it. The reason is that the water keeps the cup cool.

Another method of doing this is to take some dry stones and place them in the fire. When they are very hot, place them in a bag of water. You will need at least a couple of rocks depending on their size and how hot they are.