STEMNET Science, Technology, Engineering and Mathematics Network

We had great success in a London School showing the effects of density using tap water with a golf ball. While the golf ball sinks in regular tap water, as soon as you add significant amounts of salt, the salty water can support the golf ball. It is also possible to create a stratified salt water mix that will support the golf ball in between a layer of tap water and a layer of slat water. Food colouring can be used to illustrate this. There are also some nice videos on the internet that show how a cannon ball floats on mercury and how a can of diet coke will float in water while a regular coke will sink due to the higher sugar content. Worked really well with kids of all ages (and adults too for that matter) and I can really recommend it.