Study Guide
Quiz
November 19, 2015
HEAT TRANSFER
Vocabulary
Conduction
Convection
Electromagnetic waves
Greenhouse effect
Heat
Radiation
Temperature
Thermal energy
11/19/2015
Essential Questions
Where does heat come from
and how does it travel?
Nearly all heat in Earth’s atmosphere comes from the Sun.
What kinds of energy do we
receive from the Sun?
Most of the energy from the Sun travels to Earth as visible light and
infrared radiation (which we feel as heat). We receive a small amount
of UV radiation as well.
What happens to sunlight
when it passes through the
atmosphere?
Some sunlight is absorbed or reflected by the atmosphere before
reaching the surface, 50% is absorbed by Earth’s surface
Dust particles scatter light in all directions. Short wavelengths, (blue
Why does the daytime sky
appear blue?
and violet) are scattered more that longer wavelengths, (red and
How much of the Sun’s energy
is absorbed by the Earth’s
surface? What happens to the
energy after it’s absorbed?
About half, (50%) of the Sun’s energy is absorbed by land and water
orange). Scattered light looks blue, making the sky appear blue.
and changed into heat. When Earth’s surface is heated, it radiates
most of the energy back into the atmosphere as infrared radiation.
Heat transfer
How is Heat Transferred?
Radiation
You feel
energy
coming
directly
from the
Sun as
infrared radiation (heat).
Conduction
Direct transfer of energy by electromagnetic waves (form
of energy that can move through the vacuum of space).
Example: Warmth of Sun’s rays on your face.
The direct transfer of
heat from one
substance to another
substance that it is
touching.
Feet burned by
walking on hot sand.
Convection
Thermal Energy
Electromagnetic Waves
Temperature
Heat
In liquids and gases particles can move easily from one
place to another. As the particles move, their energy
goes along with them. The transfer of heat by movement
of particles is convection. Examples: Convection currents,
warm air rising and cold air sinking in the atmosphere.
Thermal energy is the motion of particles in matter. Thermal means “heat”.
We feel the thermal energy of particles in matter as heat. When you add
thermal energy to matter the particles move faster.
A form of energy that can move through the vacuum of space.
Average amount of energy or motion of particles in a substance. How hot
or cold. The hotter the substance, more motion of the particles in a
substance.
The transfer of thermal energy from a hotter object to a cooler object.
Page 1
Heat transfer
Three types of heat transfer working together
How do the three types of
heat transfer work together
to heat the troposphere?
Page 2


During the day, the Sun’s radiation heats Earth’s surface. Land
becomes warmer that air.
The warm surface of the Earth heats the air above it by
conduction.

Most of the air is heated by convection – the warm air rises (less
dense), as it rises it cools and becomes denser.

The cool air sinks and is heated by conduction (the heated surface
of the Earth)

The cycle begins again
Heat transfer
Green House Effect
A natural process that keeps Earth’s atmosphere
at a temperature that is comfortable for most
living things. The process by which gases
hold/trap heat in the air. Human activities that
add greenhouse gases (CO2) to the atmosphere
may be warming Werth’s atmosphere.
Possible Effects
Carbon Dioxide levels
increase
due to the burning of wood, coal,
fossil fuels, & natural gases
Ozone Depletion
Global Warming
caused by chemicals produced
by humans which may break
down ozone and damage the
ozone layer.
is the gradual increase in the
temperature of Earth’s
atmosphere
An increased amount
of UV radiation
reaching Earth’s
surface
 Change in
natural
vegetation
 Wildlife habitats
of animals
change
 Increase in sea
levels by melting
glaciers
 Less fertile fields
decreased ability
to grow crops
add carbon dioxide to the air.
Global temperatures may
increase
Can cause eye damage and
skin cancer.
Page 3
Heat transfer
Heat Transfer in the Atmosphere
Heat is the transfer of energy from a hotter object to a cooler object
How is heat transferred?
Radiation
The transfer of
solar energy by
electromagnetic
waves
Feeling the sun’s warmth
on your face
The sun’s energy is
absorbed into your
body
Page 4
Conduction
The transfer of thermal
energy from one material
to another by direct
contact
Walking barefoot on hot
sand. Your feet feel hot
because heat moved
directly from the sand to
your feet.
A pot gets hot from the
stove directly touching it
and heating it.
Convection
The transfer of
thermal energy by
circulation of a gas
or liquid
In the troposphere heat
is transferred mostly by
convection