Students (and adults) never tire of this lab. It is one of my all time favorite demo labs... important science concepts + excitment and fun! Students have a difficult time understanding we are under an 'ocean' of air, air pressure and the power of a vacuum. This lab will not only teach the concepts, it is so impressive it will become a reference point for students. In later labs you will hear them explaining... 'It works like the upside down flask and the exploding water.' What more could a science teacher want!