The atmosphere is composed of several layers - the troposphere, stratosphere, mesosphere, and thermosphere. Each layer varies in temperature and composition as altitude increases. The troposphere contains 75% of the atmosphere's mass and is where weather occurs. The stratosphere contains the ozone layer, which absorbs ultraviolet radiation and allows life to exist on Earth. Rising levels of greenhouse gases like carbon dioxide are enhancing the natural greenhouse effect and leading to issues like global climate change.

1. THE ATMOSPHERE
The atmosphere is a layer of gases surrounding the planet Earth. The atmosphere
protects life on Earth by absorbing ultraviolet solar radiation, warming the
surface through heat retention (greenhouse effect), and reducing temperature
extremes between day and night.
Atmosphere is a mixture of gases, nitrogen (78%), oxygen (21%) and other gases
in smaller quantities (1%): argon, ozone, carbon dioxide, water vapor.
STRUCTURE OF ATMOSPHERE
Scientists divide the atmosphere in four layers according to temperature layers
and the altitude.

2. TROPOSPHERE
This is the closest layer of the atmosphere to the Earth's surface, extending up
to about 10-15 kms above the Earth's surface. It contains 75% of the gases and
its temperature varies from 15ºC to -50ºC.
The tropopause is the area between troposphere and stratosphere and because of
it, the water vapor cannot go higher because it becomes ice and is trapped. The
tropopause acts like an invisible barrier and is the reason why most clouds form
and the weather phenomena occur in the troposphere.
STRATOSPHERE
It´s the second layer and it
extends from about 15 to 50 kms
above the Earth's surface. The
temperature increases with
altitude (-50ºC to 0ºC) because of
the absorption of sunlight by the
ozone. This temperature increases
with altitude, this is the opposite
situation in the troposphere.
The ozone layer blocks ultraviolet
rays which are dangerous for health.
Many jet aircrafts fly in the stratosphere because it is very stable.
The area between stratosphere and mesosphere is the stratopause.
MESOSPHERE
This layer is extending from 50 to 80 km above the Earth's surface and its
temperature is very cold (-90ºC). Meteors or rock fragments burn up in the
mesosphere. Its area is the mesopause.

3. IONOSPHERE
• This layer contains the thermosphere and exosphere and it extends from
80 km above the Earth's surface to outer space. The temperature is hot
because molecules receive a lot of energy from the sun. Those molecules
are ionized by solar radiation and it´s important because it influences, for
example, on radio propagation on the Earth. It is responsible for the
auroras borealis
© by Alan & Hui Meng
© The Regents of the University of Michigan
ACTIVITIES
1- In pairs interpret this graphic:
a) What happens to the temperature and pressure as you rise through the
Troposphere?
b) What layer includes the ozone layer?
c) In which layer does weather occur? Why?

4. d) Where is the highest temperature? How many degrees is it?
2- Look for information on the internet about the ozone holes.
a) What is it?
b) Where are the holes on Earth?
c) How are these holes made?
d) Write three things that make the ozone holes bigger.
3- Label the following things on the drawing
a) Identify layers of the atmosphere and write on the blank lines
b) Color layers of the atmosphere
c) Draw a line that identifies the ozone layer
d) Draw clouds in the layer of the atmosphere in which weather occurs
e) Draw an airplane in the layer in which the most commercial air travel
occurs

5. f) Draw a meteor shower in the appropriate layer
4- The Greenhouse Effect: Heat from the Sun warms the Earth's surface but
most of it is radiated and sent back into space. Water vapor and carbon dioxide in
the troposphere trap some of this heat, preventing it from escaping and thus
keeping the Earth warm. This trapping of heat is called the "greenhouse effect".
What are the problems about the increase of the Greenhouse effect?
Do you know why the amount of carbon dioxide
is increasing?
Look for information on the internet and after
explain what things you do to save the planet.

6. How is the Earth's atmosphere similar to a greenhouse?
What factors influence on the function of a greenhouse?
What is albedo and how is it related to understanding global climate change?
More information and games:
• http://www.windows.ucar.edu
• http://epa.gov/climatechange/kids/games
• http://www.oar.noaa.gov/k12/pdfs/gresall.pdf
• http://en.wikipedia.org
• http://www.kidsgeo.com/geography-for-kids/
5- Vocabulary:
English Spanish
layer
Warming
Surface
Greenhouse
Effect
To sent back
To trap

7. To save
Albedo
Climate change
Cloud
Weather
Sunlight
Health
Aircrafts
To burn up
Outer space
Pressure
To rise
Degrees
Ozone holes
© Maribel Gordillo2010