Chapter: Atmosphere
Table of Contents
Section 3: Air Movement
Section 1: Earth's Atmosphere
Section 2: Energy Transfer in the
Atmosphere
*What is Heat?
*Heat is energy that flows from an object with a higher temperature to an object with a lower temperature.
**This transfer of heat occurs until THERMAL
EQUILIBRIUM is reached.
Thermal equilibrium is reached when there
is no more temperature difference between
the bodies that are exchanging heat
Heat = Thermal Energy
• It depends on the vibration of the atoms
that make up the object.
• The more vibration – the higher the
temperature
Energy from the Sun
• Earth's energy comes mostly from the Sun.
• What happens with this energy once it arrives on Earth?
2
What happens with the energy from the Sun?
35% is reflected
back into space by
atmosphere and
earth's surface
65% absorbed
by the
atmosphere,
the land and
the water.
How heat is transferred within
Earth’s atmosphere
• Once it is absorbed, this energy will be
transferred by different processes:
radiation, conduction, and convection.
• Conduction Lab: What happened?
• the water in the two containers had
different temperatures
• The waters were not in contact
• the aluminum bar was in contact with
both waters and transferred the heat
from the warmer one to the colder one.
Convection: is the transfer of heat by the flow of
material (more common in liquids and gases)
The flow generates Convection Currents
• Demo – Convection: what happened?
• the warm water (red) moved up because it
is less dense.
• it cooled down, became denser
• moved to the bottom of the container,
creating convection currents.
• The convection currents mixed warm water
with cold water.
• All the water turned red and reached the
same temperature
*Climate x Weather
*Weather – is the state of the atmosphere
at a specific time and place. Ex: today is
raining
*Climate – average weather pattern in an
area over a long period of time. Ex:
Washington is humid during summer
***Importance of the heat from
the Sun
1)The energy from the Sun allows life to
exist. – warms us up, allows
photosynthesis to happen for the
production of food and oxygen.
2)**The heat from the Sun is the driving
force of weather and climate.
By warming up the water, the land and the
atmosphere, it creates the movement of
air and water.
Local weather and climate depend on
the movement of air and water around the
Earth and the atmosphere
**Movement of air – winds
**Movement of water – water cycle
**Water Cycle – is the constant movement
of water through the atmosphere,
hydrosphere and land, due to the Sun’s
energy.
The water cycle involves the processes of
evaporation, condensation, precipitation
and the flow of water on and under the
Earth’s surface.
**Water Cycle, Weather and Climate
• The processes of evaporation,
condensation and precipitation involved
in the water cycle, allow heat and
moisture to move from one area to
another
• These processes , plus the movement of
air, are responsible for weather and
climate on Earth.
Earth’s Atmosphere is Unique
*Earth’s atmosphere is unique
*It is the atmosphere that guarantees a balance between energy absorbed and reflected, creating the ideal conditions for life to exist.
• Why doesn’t life exist on Mars or Venus?
• Read the book , page 102
2
The atmosphere in Mars is very thin.
There are not enough gases to trap the Sun’s heat.
Mars is too cold and does not have enough atmosphere to support life.
There is some water in form of ice.
Why there is no life in Mars?
Venus
Venus is very hot due to the gases in its atmosphere.
Carbon dioxide: 96 percent
Nitrogen: 3.5 percent
Venus’s dense atmosphere trap heat coming from the Sun - greenhouse effect