1. Chapter 16.1
Water in the Air

2. Team Work!
In you team of 4 people…diagram the water cycle in your composition book. (section 16.1)
Label each part of the water cycle
Define each label as you go

3. Water Cycle
Definition:
The continuous movement of water from Earth’s surface (oceans and rivers) into the air (atmosphere), onto and over the land, into the ground, and back to the surface.

4. Illustration

5. Evaporation
Water from the Earth’s surface to the air, the process by which water changes from a liquid (water) to a gas (water vapor).

6. Transpiration Evaporation of water into the Atmosphere from plants.

7. Condensation
Process by which water changes from a gas (water vapor) into a liquid (water).
Cloud Formation.

8. Precipitation
Process by which water moves from the Atmosphere (clouds) to the Earth’s surface.
May be in the form of rain, sleet, snow, or hail.

9. Runoff
The movement of water that flows across land and collects in rivers and streams and eventually ends up in the oceans.

10. Putting it all together
The Water Cycle

11. The Water Cycle

12. Humidity The amount of water vapor in the air Relative Humidity=
The maximum amount of water vapor the air can hold at a given temperature.

13. Relative Humidity
This graph shows that as air gets warmer, the amount of water vapor that the air can hold increases.
When air hold all of the water vapor that it can at any given temperature, it is said to be saturated.
Saturated air has a relative humidity of 100%.

14. Factors Affecting Relative Humidity
1) Amount of Water Vapor
2) Temperature
Relative Humidity changes if either one (or both) changes

15. Measuring Relative Humidity
Psychrometer
Instrument used to measure relative humidity.
Made of wet-bulb and dry-bulb thermometers.

16. Sling Psychrometer

17. Determining Relative Humidity
Once you have both thermometer readings, you use the chart to find the relative humidity.

18. Dew Point
The temperature at which the air becomes completely saturated= 100%
Temperature of air must cool to become saturated
Thermal Energy travels from hot to cold
At this temperature gas → liquid
(Water vapor condenses into water)

19. Clouds Definition Clouds are classified by form and altitude.
A collection of small water droplets or ice crystals suspended in the air, which forms when air is cooled and condensation occurs.
Clouds are classified by form and altitude.

20. Convective Cooling… How to make a cloud!
1. Air rises
2. Molecules move apart
3. Uses potential energy
4. Lowers temperature

21. Condensation Level
The level in the atmosphere where condensation occurs.
The temperature is lower than the dew point of the air, therefore condensation occurs.
The base of the cloud is the level in the atmosphere where it’s cold enough to condense!

22. Cumulus Clouds Means “heap” Puffy, white clouds with flat bottoms
Usually indicate fair weather

23. Cumulonimbus Clouds Nimbus means “rain” Thunderstorm clouds
Tall, dense, usually dark

24. Stratus Clouds Means “layered”- form in layers
Covers large area of the sky
May bring dull and grey weather

25. Cirrus Clouds Means “curl of hair” High level clouds
Made of ice crystals

26. Altitude
Cirro- Alto Strato-
High clouds Middle Clouds Low clouds
fog

27. Cloud Types

28. Precipitation
RAIN
SLEET
SNOW
HAIL

29. Hail

30. Precipitation Rain 0.5 – 5 mm diameter Drizzle < 0.5 mm diameter
Snow = ice particles
Sleet = ice pellets form when rain falls through a layer of freezing air
Hail = solid lumps of ice form in cumulonimbus clouds