The Atmosphere

Question 1

What is the atmosphere?

Answer 1

The layer of air surrounding the Earth

Question 2

The atmosphere is made up of gases that are necessary for what?

Answer 2

• Acting as a screen and blocking out the dangerous rays from the sun (UV rays)
• Ensuring a stable climate on Earth by retaining heat
• Cellular respiration (oxygen)
• Photosynthesis (CO2)
• Water vapour

Question 3

Why does air exert pressure?

Answer 3

Because it contains particles that are colliding with one another

Question 4

What determines atmospheric pressure?

Answer 4

Particles colliding with each other.

The more collisions, the higher the atmospheric pressure

Question 5

Atmospheric pressure is measured using what?

Answer 5

Barometer

Question 6

Atmospheric pressure depends on what?

Answer 6

The height of a place above sea level and decreases with increase in altitude.

Question 7

At higher altitude, the density and temperature of the air are what? Why?

Answer 7

Lower

The number of collisions between molecules are lower and thus the pressure is lower

Question 8

When the temperature rises, what do air particles do? Consequence?

Answer 8

Air particles move away from one another so the density decreases in that specific area

Question 9

When the temperature decreases, what do air particles do? Consequence?

Answer 9

Air particles move closer together so the density increases in that specific area

Question 10

What temperature of air sinks?
Rises?
Why?

Answer 10

• Cold air sinks because it is heavier than warm air (particles move closer together so density increases)
• Hot air rises because it is lighter than cold air (particles move away from one another so the density decreases in that specific area)

Question 11

Describe convection

Answer 11

Air rises above the warm humid regions at the equator (low pressure zones), heads towards the poles and then sinks over cold, dry regions (high pressure zones)

At the same time, as the Earth rotates, the cold polar air makes its way to the equator

Question 12

What are air masses?

Answer 12

Large regions of the atmosphere with uniform temperature and humidity.

They can change the weather due to winds.

Question 13

What is a front?

Answer 13

The place where two air masses meet

Question 14

What happens when two air masses meet (how does the air move)?

Answer 14

The denser cold air slides beneath the lighter warm air

Question 15

Describe a warm front.

Answer 15

A warm air mass moving into a cold mass

Question 16

Describe a cold front.

Answer 16

A cold air mass moving into a warm mass

Question 17

What happens to the moisture in the air as it cools when fronts meet?

Answer 17

It forms clouds

Question 18

Is a warm front a low or high pressure system?

Answer 18

Low-pressure (because hot air rises)

Question 19

When does a warm front form? Describe what happens.

Answer 19

When a mass of warm air moves towards a mass of cold air.
The warm air rises over the cold air and creates HEAVY, stratified clouds resulting in cloudy weather and light, scattered showers
-> Associated with clouds and precipitation (bad weather)

Question 20

When does a cold front form? Describe what happens.

Answer 20

Occurs when a mass of cold air (high-pressure) meets a mass of warm air (low-pressure)
The warm air rises rapidly and in a steep slope over the cold air, and then cools
-> Normally associated with dry weather and mostly clear skies with fluffy clouds
(enough moisture/temperature contrast = thunderstorm)

Question 21

Describe depressions.

Answer 21

1. Air gets warm, particles move away from one another and the air mass becomes less dense
2. The air mass becomes lighter and rises, leaving an empty space under it. This is called a depression. The space becomes an area of low pressure.
3. Rising air encourages cloud formation and often results in precipitation.

Question 22

Describe anticyclones.

Answer 22

1. When air sinks, the pressure rises
2. The air density then increases and the mass of air becomes heavier, and sinks toward the ground creating an area of high pressure. This area is called an anti-cyclone (H on weather charts)
3. Cold air, sinking does not favour cloud formation so this phenomena results in clear skies and stable weather

Question 23

Strong depressions form where? What is this called?

Answer 23

Often form over warm waters of tropical oceans. A huge spiral with heavy winds then forms.
This is called cyclone/hurricane/typhoon

Question 24

What is the greenhouse effect?

Answer 24

A natural process that allows the Earth to keep some of the heat it receives from the sun.

Question 25

Name the GHGs

Answer 25

H2O (water vapour)
CO2 (carbon dioxide)
CH4 (methane)
Nitrous oxide

Question 26

What are humans doing to increase GHGs?

Answer 26

Meat eating, digestion of cows=more CH4
Deforestation = less photosynthesis
Combustion (factories)

Question 27

What temp would the Earth be at without GHGs?

Answer 27

-18 C

Question 28

How does the greenhouse effect work?

Answer 28

• Most of the suns rays are absorbed by the Earths surface
• Once the surface is heated, some of the heat is emitted infrared rays into the atmosphere and some of those rays escape back into space
• Greenhouse gases trap some infrared rays and send them back to Earth warming its surface even more

Question 29

STUDY: The intensification Greenhouse Effect

Answer 29

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