1. Weather Cathcart 6 th grade science

2. What is weather? Weather is the condition of the atmosphere at a certain time and place.

3. What kinds of conditions are there? Conditions vary depending on temperature, humidity, precipitation, and wind. Changes in conditions can be predicted by analyzing the data.

4. What is humidity? Humidity is the amount of water vapor in the air. Water vapor is water in a gas form. Water vapor is not visible.

5. Water Vapor Steam is NOT water vapor. Water vapor is not visible.

6. What is relative humidity? Relative humidity is the ratio of the amount of water vapor in the air, to the amount of water vapor the air can possibly hold. The maximum amount of water vapor the air can hold is called saturation. Actual water vapor X 100 = relative humidity (%) saturation

7. How much water vapor can air hold? The temperature affects how much water vapor air can hold. The warmer the air, the more water vapor it can hold.

8. What is condensation? When water vapor turns from a gas into a liquid, this is called condensation.

9. Condensation Air next to a cold drink cools. When it cools, it can’t hold as much water vapor. Some of its water vapor condenses into liquid water on the glass.

10. What is dew point? The dew point is the temperature where water in the air condenses into liquid water.

11. Dew When air cools over night, it may reach its dew point. Some of the water vapor in the air condenses. Dew makes the grass wet early in the morning.

12. What are clouds? Clouds are a collection of millions of tiny water droplets or ice crystals.

13. Clouds are not water vapor. Clouds are where water vapor condensed onto tiny particles in the air.

14. What is precipitation? Precipitation is when water from the air returns to earth. The can be in the form of snow, rain, hail or sleet.

15. What is an air mass? An air mass is a large body of air with the same temperature and humidity throughout.

16. What is a front? A front is the boundary between air masses. The air masses usually have different temperatures and densities.

17. Remember: Warm air is less dense and tends to rise. Cooler air is more dense and tends to sink.

18. What is a psychrometer? A psychrometer is an instrument that measures relative humidity.

19. What is a thermometer? A thermometer is an instrument used to measure the temperature of the air.

20. What is a barometer? A barometer is an instrument used to measure air pressure.

21. What is a windsock? A windsock is an instrument used to measure the direction of the wind.

22. What is an anemometer? A anemometer is an instrument that measures the speed of the wind.