1. The Water Cycle p. D34-D37

2. What happens during the water cycle?
Water is recycled.
It changes from a liquid to a gas.
Then the gas changes back to a liquid.

3. What forces make the water cycle work?
Sun
Water
Air
Land

4. Evaporation
The sun warms the ocean, causing the water to enter the air as water vapor.
This is the change from liquid to gas.

5. Condensation
Water vapor high in the atmosphere cools and changes from a gas to a liquid.
These water drops form clouds.

6. Precipitation
Inside clouds, water drops hit each other and stick together.
Eventually they become too big to stay in the air.
They fall to earth as rain, sleet, snow, or hail.

7. More About Precipitation
Some precipitation collects in lakes, rivers, and other bodies of water.
Some soaks into the ground.
Some falls back into the ocean.

8. Ocean Water
Ocean water is a mixture of water and dissolved solids, mostly salts.
Sodium chloride is the most common ocean salt. You know it as “table salt”.

9. Why is ocean water salty?
Most of the salt comes from land.
Water flowing over land breaks away rocks.
Over time, salts from these broken rocks enter the oceans.

10. Salt Water Facts
Ocean water is a bit saltier near the equator, because it is hotter and evaporation occurs faster. (salt is left behind)
Ocean water is less salty near the poles, because it is colder. There is less evaporation here. (warmth is needed for evaporation)

11. Final Thought
Water vapor entering the air from the ocean has lost its saltiness.
This is why precipitation falls as fresh water instead of salty water.