UNIT 8:THE ATMOSPHERE

OBJECTIVES

1. To study the composition of the atmosphere.

2.To learn about wind formation.3.To study how clouds are formed.4.To study the different types of precipation.5. To understand the importance of the

atmosphere.6. To investigate atmospheric pollution.

COMPOSITION AND STRUCTURE OF THE ATMOSPHERE

The atmosphere is the fluid outer layer that surrounds the Earth.

It’s made up of nitrogen, oxygen and other gases like carbon dioxide and argon.

78%

21%

1%

There are five layers: Troposphere Stratosphere Mesosphere Termosphere Exosphere

ACTIVITIES1.Write the name of the atmospheric layer:

a) About 12Km thick. It contains 80% of the air.

b)From 50 Km to 80 Km.

c)The outer layer. From 500Km to 10.000Km

d)It’s also called ionosphere. Gases absorb harmful solar radiation.

e)From 12Km to 50Km. The ozone layer is found here.

2.Copy and complete the sentence: Atmospheric air is made up of 78% of……,21% of……. And other gases like…….

3. Circle the right word:

a) The ozone layer retains / protects us from harmful solar radiation.

b) The layer furthest / nearest to the Earth is the troposphere.

c) The stratosphere contains horizontal / vertical layers of gas.

d) The termosphere reflects / absorbs radio waves back to Earth.

The atmosphere regulates temperature because water vapour and carbon dioxide absorb solar radiation and heat up the Earth’s surface. (greenhouse effect)

The atmosphere is a shield. It protects us from harmful radiation such as gamma

rays, X-rays,ultraviolet rays. It protects us from the impact of meteorites.

The atmosphere is essential for living things. We need oxygen to breath and plants need CO2 to make

photosynthesis.

THE IMPORTANCE OF THE ATMOSPHERE

GREENHOUSE EFFECT AND GLOBAL WARMINGGlobal warming is the rise in temperature of the Earth’s atmosphere.Greenhouse gases are all natural gases, but extra greenhouse gases can be made by humans, and that is harmful.

ACTIVITIES

4. Why the atmosphere is so important?5. List three examples of harmful radiation.6. Explain why greenhouse effect is good.7.Why human activity is causing global

warming?

Atmospheric pressure is the weight of the atmosphere on the Earth.

The international unit for pressure is the pascal (Pa).

We normally use the atmosphere (atm) or the millibar (mb). 1 atm=1013 hPa=1013 mb

Normal pressure is the pressure at sea level (1 atm)

Atmospheric pressure varies with altitude.

ATMOSPHERIC PRESSURE

ACTIVITIES

8. What is atmospheric pressure?

9. Why does atmospheric pressure decrease when we climb a mountain?

Air moves from high pressure areas to low pressure areas. This circulation of air is called wind.

A low pressure area is called depression. The warm air rises.

A high pressure area is called anticyclone. The cold air descends.

WIND FORMATION

Anticyclone

Depression

ACTIVITIES

9. How is called a high pressure area?10. How is called a low pressure area?11. The air rise in a _______ ___________

area.12.The air descends in a _______ ________

area.13. Draw a depression and an

anticyclone.

Hurricane WhirlwindTornado

CLOUD FORMATION

1

2

3RAIN

SNOW

HAIL

ACTIVITIES

14. Write three atmospheric phenomena caused by the wind.

15. Write four atmospheric phenomena caused by condensation of water vapour.

16. Write three atmospheric phenomena caused by precipitation of water vapour.

17. Label each photograph according to wind phenomena.

a) b) c)

18. Identify these photos according water vapour phenomena

a) b) c) d)

e) f) g)