1. Chapter 9: The Water Cycle
Lesson 1: What Is The Water Cycle?

2. Water Cycle- The movement of water from the surface of Earth into the air and back again.
Precipitation- Water that falls to Earth.
Evaporation- The process by which a liquid changes into a gas.
Condensation- The process by which a gas changes into a liquid.

3. 1. What steps must take place in order for ocean water to become rain?
The water must be warmed by the sun, go into the air as gas, cool down and become water again, and then fall back to Earth as rain.
2. How does water on Earth’s surface enter the air?
Heat causes it to change from liquid to gas.
3. How do clouds form?
Water vapor in the air condenses.
4. How does water move from the air to Earth’s surface?
Water droplets or ice crystals in clouds fall to the ground
5. How does water enter rivers and streams?
Precipitation falls into the rivers and streams, or runoff from precipitation flows into rivers and streams.

4. 6. What energy source drives the water cycle?
The sun
7. What is precipitation and how does it form?
Precipitation is rain, snow, sleet, or hail that falls from the air to Earth. Precipitation forms when water droplets get too large to stay in the air.
8. What happens to energy from the sun when it changes liquid water into a gas form?
The sun’s energy changes to heat energy in the water particle.
9. When water evaporates what form does it take?
Gas or water vapor
10. When water condenses, what form does it take?
Liquid water

5. 11. Explain the sequence in which precipitation forms in a cloud?
First, water condenses in the cloud. Then, small drops of water form. Next, small drops of water collide and form larger drops of water. Finally, the drops of water become so heavy that they fall out of the cloud.
12. What makes up clouds?
Particles of dust and condensed water
13. What happens to water soaked up by soil?
Plants use some of the water and some is evaporated back into the air. The rest of the water soaks deeper into the ground until it reaches solid rock. There, it becomes part of a body of groundwater.
14. What is runoff?
Runoff is precipitation that lands on Earth’s surface but isn’t soaked up by soil.

6. 15. How does groundwater form?
Rainwater soaks into the soil and moves deeper into the ground until it reaches solid rock. The water collects on top of the solid rock.
16. When water vapor cools what happens?
Condensation