Science- balloon in jar with Mr Cook!

Today we had Mr Cook and we did some science. First you need a jar, butter, hot water, tea towel, balloon, and a pencil. you cover the balloon with butter then tip hot water into the jar put the tea towel on the top of the jar and shake it. Take the tea towel off and push the balloon into the jar. To get the balloon out put the pencil next to the balloon and pull the balloon and pencil out.