Transcript Chapter 2 Weather Factors

Chapter 2
Weather Factors
7ht G rad e S cien ce
Section 1: Energy in
Earth’s Atmosphere
Objectives:
State in what form energy
travels form the sun to Earth.
Explain what happens to the
sun’s energy in the atmosphere
at Earth’s surface.
The movement of heat in the
atmosphere causes temperature
to change, winds to blow, and
rain to fall.
Nearly all the energy in Earth’s
atmosphere comes from the sun.
This energy travels to Earth as
electromagnetic waves, a
form of energy that can move
through the vacuum of space.
Radiation is the direct transfer
of energy by electromagnetic
waves.
Most of the energy form the sun
travels to Earth in the form of
visible light and infrared
radiation. A small amount
arrives as ultraviolet radiation.
Visible light includes all of the colors
that you see in a rainbow.
Infrared radiation is electromagnetic
energy that can be felt as heat.
Ultraviolet radiation is
electromagnetic energy that can cause
sunburns, skin cancer, and eye damage.
Some sunlight is absorbed or
reflected by the atmosphere
before it can reach the surface.
The rest passes through the
atmosphere to the surface.
Dust particles and gases in the
atmosphere reflect light in all
directions, a process called
scattering.
When Earth’s surface is heated,
it radiates most of the energy
back into the atmosphere as
infrared radiation.
The process by which gases hold
heat in the air is called the
greenhouse effect.
Click below to watch a BrainPop
on the Greenhouse Effect.
Section 2: Heat Transfer
Objectives:
Describe how temperature is
measured.
Identify three ways in which heat is
transferred.
Explain how heat is transferred in
the troposphere.
Heat transfers through our
environment all of the time.
Things are always getting
warmer or cooler.
Temperature is the average
amount of energy of motion of
each particle of a substance.
Thermal energy is the
total energy of motion in the
particles of a substance.
Air temperature is usually
measured with a
thermometer.
A thermometer is an
instrument used to measure
temperature.
Heat is the transfer of
thermal energy from a
hotter object to a cooler
one.
Heat is transferred in three
ways…
3 Types of Heat Transfer
1. Radiation - the transfer of
heat by electromagnetic waves
Examples of Radiation
* Sun warming Earth
* Camp fire
* Microwave oven
* Light Bulb
2. Conduction - the transfer
of heat from one substance to
another substance that it is
touching
Examples of Conduction
* Ironing a shirt
* Feet on hot sand
* Spoon in hot liquid getting
warm
* Stove making a pot get hot
3. Convection - the transfer
of heat by the movement of a
fluid(liquids and gases)
Examples of Convection
* Warm water rising to top in
pool
* Stove heating up and
warming room
* Earth’s mantle
* Lava Lamp
Radiation, conduction, and
convection work together to
heat the troposphere.
Within the troposphere, heat is
transferred mostly by
convection.
The upward movement of
warm air and the downward
movement of cool air form
convection currents.
Check out this Heat Transfer Website