STUDY GUIDE: WATER IN THE ATMOSPHERE - ANSWER KEY

Complete #1-9 using the Dew Point & Relative Humidity Tables and the Cloud Base Graph: (Found on the page protected handout or available online.)

Air
Temp. / Dew
Point / Cloud Base
Altitude
7. / 22⁰C / 20⁰C / .25 km
8. / 6⁰C / 2⁰C / .5 m
9. / 12⁰C / 12⁰C / 0 km
Dry-Bulb
Temp. / Wet-Bulb
Temp. / Dew
Point
1. / 22⁰C / 20⁰C / 19°C
2. / -2⁰C / -6⁰C / -20°C
3. / 12⁰C / 12⁰C / 12°C
Dry-Bulb
Temp. / Wet-Bulb
Temp. / Relative
Humidity
4. / 22⁰C / 20⁰C / 83%
5. / 4⁰C / -1⁰C / 27%
6. / 12⁰C / 12⁰C / 100%

10. The actual amount of water vapor in the air is called Specific Humidity. The amount of water vapor in

the air compared to the maximum amount of water vapor the air can hold is called Relative Humidity.

11. Are clouds made up of water vapor or liquid water? Liquid Water

12. What role does condensation nuclei have in cloud formation? Water vapor cannot condense into liquid water without something solid to attach onto so specks of dust or salt particles in the air allow water to condense around it to form cloud drops.

13. Give an example of something that could act as condensation nuclei: tiny specks of dust or salt in the air

14. Sometimes, when you wake up in the morning, there are drops of water on the grass, but it did not rain. What happened overnight to cause this? The temperature dropped below the Dew Point and the water vapor in the air condensed into liquid water.

15. What does it mean when the air is saturated? It has reached 100% capacity can’t hold any more water vapor.

16. Explain the difference between weather and climate: Weather is the state of the atmosphere at a given place and time, and changes daily. Climate is an area’s long-term weather patterns (usually in averages).

17. List all the factors that determine an area’s climate: Latitude, Vegetation, Elevation, Prevailing Winds, Nearby Water, Ocean Currents, Topography

18. What three factors influence weather? Air Pressure, Temperature, Precipitation

19. The temperature at which the air is saturated with water vapor is referred to as Dew Point.

20. Which of the volumes of air below would be able to hold the most water vapor? [ A , B , C , D ]

Explain: Container ‘D’ has the highest temperature, and warmer air can hold more moisture than cold air.

21. What is the name of the instrument that is used to measure humidity? Psychrometer

22. Does precipitation occur on the windward or leeward side of a mountain? Windward

23. Does the rain shadow occur on the windward or leeward side of a mountain? Leeward

Why? Winds carry air toward the mountains and as the air rises up, the air cools, water vapor condenses, clouds form and it rains on the windward side. Once the air passes over the mountain range, it has dried out and it moves down the other side creating a higher pressure area with no rain.

24. As the temperature of the air cools gets closer to its Dew Point, what happens to the Relative Humidity?

It increases. Cooler air cannot hold as much moisture as warm air, so as the temperature decreases, the percentage of water vapor in the air increases (even though the amount of water vapor stays the same).

25. What latitudes would you expect to find the most precipitation? Equator, 60o N & S

Why? Low pressure generally occurs at those latitudes

26. What instrument is used to measure liquid precipitation? Rain Gauge

27. What instrument is used to measure frozen precipitation? Measuring Stick

28. Write the name of the process that describes the change in the state of water below:

Label each diagram below with the correct type of Precipitation shown: (Sleet, Rain, Freezing Rain, or Snow)

33. How does hail form? Hail forms in a cumulonimbus cloud when strong updrafts carry rain drops high up into the cloud where temperatures are below freezing. Hailstones can grow as additional water freezes onto it. Eventually, the hailstone becomes too heavy and it falls to the ground.

34. Clouds are classified by their shape and altitude

35. Clouds that form in layers are called stratus

36. High, feathery ice clouds are called cirrus

37. Fluffy clouds with flat bases are called cumulus

38. Dark rainclouds are called nimbostratus / cumulonimbus

39. Clouds that produce lightning and hail are called cumulonimbus

40. Clouds form in the layer of the atmosphere called the troposphere

41. Label the Water Cycle diagram: Precipitation, Evaporation, Runoff, Transpiration, Condensation