Summarize the main idea of a reading, create visual aids, and come up with new questions using a Four Square Concept Matrix.
Some substances can change phase directly form a solid to a gas. This is called sublimation. Dry ice and snow under certain conditions can sublimate.
The total amount of water above, on and in Earth is not very much. Since most of this water is not usable, the usable parts must be taken care of.
Water in Yosemite runs down creeks, rivers and waterfalls; the rivers flow into the Central Valley where they are used for irrigation or municipal purposes. Conserving water keeps water available for wilderness.