In this earth science unit children explore water and its properties. They discover where it can be found, its forms, how it can be used, and how it can change in form. Children learn about surface water such as rivers, waterfalls, ponds, lakes, streams, and oceans and discuss the differences between the various bodies of water. They gain an understanding that water is in the air, underground, and in the oceans. Children discuss differences between fresh water and salt water and learn that there is more salt water than fresh water, thus making fresh water a valuable resource. They compare the amount of land and water on earth. Children identify sources of drinking water such as wells, rivers, springs, and the Great Lakes. They investigate various uses of water including drinking, cleaning, food preparation, generating electricity, recreation, irrigation, farming, transportation, and industry. Children look at which uses consume more water than others, the misuses of water, and ways water can be conserved. They explore how water changes form and learn about two of the three states of water, solid and liquid (ice, liquid water).