The Earth's atmosphere consists of several layers including the troposphere, stratosphere, mesosphere, and thermosphere. The troposphere contains most of the weather and extends from the Earth's surface to about 10 km. Above that, the stratosphere contains much of the ozone layer which protects the Earth from UV radiation. The mesosphere is a cold layer above the stratosphere where temperatures decrease with altitude. Above that, the thermosphere contains the ionosphere and absorbs solar radiation, causing temperatures to rise dramatically with altitude.

1. The Earth’s
Atmosphere

2. ATMOSPHERE
It is the combined gases or air
that surrounds the earth.
Atmosphere is very important
for it protects human from the
scorching heat of the sun
through its ozone layer.

3. COMPOSITION OF GASES
IN THE ATMOSPHERE

5. LAYERS OF THE ATMOSPHERE

6. TROPOSPHERE
 This is the lowest part of the atmosphere - the part we live in.
It contains most of our weather - clouds, rain, snow. Air
pressure drops, and temperatures get colder, as you climb
higher in the troposphere.

7. STRATOSPHERE
 This extends upwards from the
tropopause to about 50 km. It
contains much of the ozone in the
atmosphere. The increase in
temperature with height occurs
because of absorption of ultraviolet
(UV) radiation from the sun by this
ozone. Temperatures in the
stratosphere are highest over the
summer pole, and lowest over the
winter pole.

8. MESOSPHERE
 Directly above the stratosphere, extending from
50 to 80 km above the Earth's surface, the
mesosphere is a cold layer where the
temperature generally decreases with increasing
altitude. Here in the mesosphere, the
atmosphere is very rarefied nevertheless thick
enough to slow down meteors hurtling into the
atmosphere, where they burn up, leaving fiery
trails in the night sky.

9. THERMOSPHERE
 The layer of very rare air above the mesosphere is called
the thermosphere. High-energy X-rays and UV radiation from the Sun
are absorbed in the thermosphere, raising its temperature to hundreds
or at times thousands of degrees. However, the air in this layer is so thin
that it would feel freezing cold to us Many satellites actually orbit
Earth within the thermosphere!

10. Ionosphere
 Ionosphere is a series of regions in
parts of the mesosphere and
thermosphere where high-energy
radiation from the Sun has knocked
electrons loose from their parent atoms
and molecules. The electrically charged
atoms and molecules that are formed
in this way are called ions.

11.  It is also in the thermosphere where the aurora
borealis or ‘northern lights’ is located most
specifically in the northern hemisphere.
 The most common aurora colour which is
green, is produced by oxygen molecules
located about 60 miles above the earth. The
rarer red auroras are produced by high-altitude
oxygen, at heights of up to 200 miles. Nitrogen
produces blue or purple aurora.
 The best places to watch the aurora are usually
are North America or Europe.

12. TRANSFER OF HEAT/ENERGY
 The motion of atoms and
molecules creates heat or thermal
energy. All matter has this thermal
energy. The more motion the
atoms or molecules have the more
heat or thermal energy they will
have.

13. CONDUCTION
 Conduction is the transfer of heat
between substances that are in
direct contact with each other. The
better the conductor, the more
rapidly heat will be transferred.
 Metals are good conductors of
heat, but non-metals and gases are
usually poor conductors. Poor
conductors are called insulators.

14. EXAMPLES OF CONDUCTION:
 Touching a stove and being burned
 Ice cooling down your hand
 Boiling water by thrusting a red-hot piece of iron into it

15. CONVECTION
 Thermal energy is transferred
from hot places to cold places by
convection. Convection occurs
when warmer areas of a liquid or
gas rise to cooler areas in the
liquid or gas. Cooler liquid or gas
then takes the place of the
warmer areas which have risen
higher.

16. EXAMPLES OF CONVECTION:
 Hot air rising, cooling, and falling
(convection currents)
 An old-fashioned radiator (creates a
convection cell in a room by emitting
warm air at the top and drawing in
cool air at the bottom).
 Water boiling in a pan
 The earth's surface is warmed by the
sun, the warm air rises and cool air
moves in.

17. RADIATION
 Radiation is a method of heat transfer
that does not rely upon any contact
between the heat source and the heated
object as is the case with conduction and
convection. Heat can be transmitted
through empty space by thermal
radiation often called infrared radiation.
This is a type electromagnetic radiation .
No mass is exchanged and no medium is
required in the process of radiation.

19. EXAMPLES OF RADIATION
 the heat from the sun
 heat released from the filament of a light bulb.
 Dying clothes in the open air
 Heat from the sun warming your face
 Heat from a lightbulb
 Heat from a fire
 Heat from anything else which is warmer than its surroundings.

20. EXAMPLES

23. QUIZ