Density is often measured by whether an object floats or sinks in water. Real Japanese
1 Yen coins are made from aluminum and can be made to float on the surface of a cup of water.
Giant Pumice is the largest volcanic pumice sample we have ever seen... and it still floats!
Lignum Vitae is one of the few species of wood that sink in water. Powered by baking powder, the
Diving Submarine dives and surfaces just like a real submarine.
