Water evaporates from the surface of the earth, rises and cools, condenses into rain or snow, and falls again to the surface. The water falling on land collects in rivers and lakes, soil, and porous layers of rock, and much of it flows back into the oceans. The cycling of water in and out of the atmosphere is a significant aspect of the weather patterns on Earth.
Learning Goal 8
Fresh water, limited in supply, is essential for some organisms and industrial processes. Water in rivers, lakes, and underground can be depleted or polluted, making it unavailable or unsuitable for life.
Learning Goal 10ab
Some material resources are very rare and some exist in great quantities. The ability to obtain and process resources depends on where they are located and the form they are in. As resources are depleted, they may become more difficult to obtain.
Learning Goal 11a
The wasteful or unnecessary use of natural resources can limit their availability for other purposes. Restoring depleted soil, forests, or fishing grounds can be difficult and costly.
Learning Goal 11bc
The benefits of Earth's resources—such as fresh water, air, soil, and trees—can be reduced by deliberately or inadvertently polluting them. The atmosphere, the oceans, and the land have a limited capacity to absorb and recycle waste materials. In addition, some materials take a long time to degrade. Therefore, cleaning up polluted air, water, or soil can be difficult and costly.
The Structure of Matter
For Grades: 3-5
Learning Goal 1a
Heating and cooling can cause changes in the properties of materials, but not all materials respond the same way to being heated and cooled.
Learning Goal 1b
Many kinds of changes occur faster under hotter conditions.
For Grades: K-2
Learning Goal 1
The sun warms the land, air, and water.
For Grades: 3-5
Learning Goal 2b
When warmer things are put with cooler ones, heat is transferred from the warmer ones to the cooler ones.
Learning Goal 2c
A warmer object can warm a cooler one by contact or at a distance.