Why is it easier to float on the ocean than on a lake? It’s because salty water is denser than fresh water. Whenever ocean water and fresh water meet, the saltier water sinks. Saltiness, or salinity, has a profound effect on ocean currents, too. Of course, so does heat, since warm water is less dense than cold water. These two simple facts, so important to understanding Earth’s climate, are demonstrated in this new game. Use salt and heat tools to create currents that will carry you to treasure.
http://1.usa.gov/xmVFXD
