5.4 ATMOSPHERE

DEFINITION

•Atmosphere:

•The layer of gas

surrounding the Earth

GREENHOUSE GAS EFFECT

•What is it?

•The gases in the atmosphere

help trap heat like the

windows of a greenhouse

making the Earth warmer

than it would be without

them

GREENHOUSE GAS EFFECT

•Without the greenhouse gas effect, the average

temperature on Earth would be -18°C

•With the greenhouse gas effect, the average temperature on Earth is +15°C

GREENHOUSE GAS EFFECT

SO WHY DO WE CONSIDER IT A BAD THING?

•The greenhouse effect is

generally a good thing

• Important for sustaining life

SO WHY DO WE CONSIDER IT A BAD THING?

• The problem is that that humans have created processes (ex: burning

fossil fuels) that releases more

greenhouse gases than is natural

• This is causing the Earth to keep too

much heat in

•We’re making the planet too warm

COMPOSITION OF THE ATMOSPHERE

•Air is a homogeneous mixture

with two main gases!

•Nitrogen (79%) and Oxygen

(21%)

•Carbon Dioxide (0.03%)and

other gases (0.97%) are found

in small quantities

LAYERS OF THE ATMOSPHERE

• There are five main layers of the

atmosphere:

1. Troposphere (0-20 km)

2. Stratosphere (20-50 km)

3. Mesosphere (50-85 km)

4. Thermosphere (85-690 km)

5. Exosphere (690-10 000 km)

TROPOSPHERE

• Layer that contacts the ground

• Contains the gases necessary for life (80% of them)

• Clouds form here

• The higher you go,

the colder it gets

STRATOSPHERE

•Where you’ll find the ozone layer

• Layer that blocks UV rays from the

sun

• The higher you go,

the warmer it gets

•Where airplanes fly

MESOSPHERE

• Meteoroids break up here! (Shooting stars)

• Have large temperature variations here

• The higher you go, the colder it gets

THERMOSPHERE

• The higher you go, the

hotter it gets; hottest

temperature reaches 1500°C

• Where satellites are

found and the

international space

station

• Site of the Polar

Auroras

EXOSPHERE

•The outermost part of the atmosphere that is still considered to be part of Earth

•Contains only a few particles that move into and out of space

•More satellites are found here