Science ~ chapter 8 weather

1. Science ~ chapter 8weather Miss Nelson

2. Section 2 Precipitation

3. Anticipatory set What types of precipitation have you personally experienced? How are they different from one another?

4. standards S 6.4.e – Students know differences in pressure, heat, air movement, and humidity result in change in weather

5. The big idea What are the common types of precipitation?

6. Key terms • Precipitation – any form of water that falls from the clouds and reaches Earth’s surface

7. precipitation • Water evaporates from every water surface on Earth and from living things • Eventually, this water returns to the surface as precipitation • Not all clouds produce precipitation • For precipitation to occur, cloud droplets or ice crystals must grow heavy enough to fall through the air

8. Types of precipitation Common types of precipitation include: • Rain • Hail • Snow • Sleet • Freezing rain

9. rain • Most common kind of precipitation • Droplets are called rain if they are at least .5 millimeters in diameter • Smaller = drizzle • Smaller than that = mist • Drizzle/mist usually fall from stratus clouds

10. hail • Round pellets of ice larger than 5 millimeters in diameter are called hailstones • Hail forms only inside cumulonimbus clouds during thunderstorms View the diagram on page 308 of your textbook

11. snow • Often, water vapor in a cloud is converted directly into ice crystals • Called snowflakes • Have an endless number of different shapes and patterns • All have six sides and branches • When snow falls through humid air that is close to freezing, the snowflakes tend to join together into larger clumps

12. sleet • When raindrops fall through a layer of air that is below 0 degrees Celsius (the freezing point of water) they freeze into solid particles of ice • Ice particles smaller than 5 millimeters in diameter are called sleet

13. Freezing rain • Sometimes raindrops falling through cold air near the ground do not freeze in the air • Instead, they freeze when they touch a cold surface • Called freezing rain

14. Types of precipitation Read Types of Precipitation on pages 308-309 of your textbook

15. Check for understanding What are the five common types of precipitation? What is the difference between freezing rain and sleet?

16. Check for understanding What are the five common types of precipitation? The five common types of precipitation are rain, sleet, freezing rain, hail, and snow. What is the difference between freezing rain and sleet? The difference between freezing rain and sleet is that freezing rain is water that freezes when it touches a cold surface, where as sleet is water that freezes in the air.

17. Guided practice How does hail form? Hail forms start as small pellets of ice in cumulonimbus clouds. They grow larger as they are repeatedly tossed up and down, until they become so heavy that they fall to the ground. A thunderstorm produces precipitation in the form of ice particles that are about 6 millimeters in diameter. What type of precipitation is this? This type of precipitation is hail.

18. Independent practice Complete Weather 8-2 Independent Practice