Chapter 17 Study Guide Answers

1. What is weather?

the state of the atmosphere at a given time and place

- controlled by Earth’s motions & energy from the sun

2. What is climate?

the given weather conditions of an area over many years

avg. rainfallavg. tempavg. humidityavg. wind directionavg. air pressure etc…

3. What is the current composition of our atmosphere? Give gases & %

Current composition of atmosphere: 78% Nitrogen 21% Oxygen 0.93% Argon (inert gas) 0.039% Carbon DioxideAlso present in atmosphere = water vapor, dust, ozone, and pollution

OZONE

4. O3

5. Found in the stratosphere- between 10-50 km from surface, it increases the temperature

6. Blocks harmful Ultraviolet (UV) rays

7. 4 layers of atmosphere

Troposphere = temperature decreases as you increase altitude- Extends from surface to ~12 km- All weather occurs here

Stratosphere = slight increase in temperature- Extends from 12km to ~50 km- Contains the Ozone Layer (absorbs UV to increase temperature)

Mesosphere = temperatures decrease with altitude- No definite upper limit - Temperatures near -90ºC

Thermosphere = temperatures increase due to absorption of high energy solar radiation- No definite upper limit

8. What layer does weather occur?

Troposphere- all weather phenomena

9. How much of the sun’s energy is reflected back into space?

~30% is reflected back into space

10. What is reflection?

When light bounces off an object

11. What is scattering?

When weak light rays travel in different directions

12. What is conduction?

Conduction = transfer of heat through direct contact of molecules

heat flows from the hotter object into the colder object

13. What is convection?

Convection = transfer of heat by mass movement or circulation within a substance

heat from below (ground) conducts heat near the base of the atmosphere, the air

14. What is radiation?

Radiation = heat is radiated (travels by waves) from the sun and hits the atmosphere

some radiated energy is absorbed and some is reflected (bounced) back into space:

~30% is reflected back into space~50% is absorbed by land & sea~20% is absorbed by clouds & atmosphere

15. Greenhouse effect..why is it good?

Earth’s atmosphere naturally absorbs heat from the sun because of water vapor & carbon dioxide

atmosphere traps heat near the Earth’s surface

Without this natural greenhouse effect, Earth’s temperature would be much colder (uninhabitable for humans)

16. Global warming…why is it bad?

Global warming is an increase in temp. of Earth’s atmosphere that may be caused by human activity

Affects overall climate and animal habitats

17. 5 factors that influence temp. on Earth

LatitudeHeating of land & waterAltitudeGeographic positionCloud cover

18. How does latitude affect Earth’s temp?

Latitude (distance from the equator)

Differences in amount of solar radiation received

Variations in the angle of sun’s rays

Length of daylight

19. Why do land & water have diff temps?

Land heats more rapidly and to higher temperatures than water

- Land also cools more rapidly and to lower temperatures than water

- Cities near water have a smaller daily temperature change

compared to cities more inland

20. What happens to temp. as you increase altitude

The higher the altitude, the colder the temperatures

21. When does summer solstice occur?

On June 21 or 22

21. When does winter solstice occur?

On December 21 or 22

23. When does spring equinox occur?

March 21 or 22

24. When does autumnal equinox occur?

September 22 or 23

25. What is the tilt of Earth’s axis

23.5º

26. What causes seasons?

The tilt of the Earth’s axis

27. What are isotherms?

Line on a map connecting points of equal temperature

28. What is albedo?

Albedo- the fraction of total radiation that is reflected by any surface

29. Clouds and keeping Earth cool & warm..

Day- clouds reduce radiation and keep it cooler. No clouds means it’s warmer.

Night- it’s the opposite; clouds act like a blanket & keep it warm. A clear night means it’s cooler