bottle have caved in a little.
then we tried to do the egg in the bottle experiment also playing with the volume of air at different temperatures. this experiment has given me no end of grief. the idea is simple as is the science behind it. you have heated air in a container. in the usual version of this experiment the air is heated by a lighted match stick dropped into the bottle. you then place an egg on top of the container and, as the air cools, the air inside the container takes up less space. the egg has allowed the heated air leave the bottle, but does not let 