Weather Factors
Chapter 16
Energy in Earth’s Atmosphere
 Heat is a major factor in the weather
 Movement of heat in the atmosphere causes the
temperatures to change, winds to blow, and rain to fall
Energy from the Sun
 Nearly all the energy in Earth’s atmosphere comes from the SUN.
 The energy travels to Earth as ELECTROMAGNETIC WAVES, which is
a form of energy that can move through the vacuum of space. Ewaves are classified as WAVELENGTHS, which is the distance
between waves.
 RADIATION is the direct transfer of energy by e-waves.
 Most energy from the sun travels to Earth in the form of VISIBLE
light and INFRARED radiation.
 Small amounts arrive as ULTRAVIOLET radiation.
NEED TO KNOW:
** Electromagnetic waves (e-waves) are energy
** Radiation is the direct transfer of e-waves (energy)
** It travels in the form of visible light, infrared radiation, and small
amounts of UV radiation.
LONGER WAVELENGTHS
SHORTER WAVELENGTHS
Visible Light
 All colors you see in the rainbow
 Different colors are the result of different WAVELENGTHS
 What color is the longest wavelength?
 What color is the shortest wavelength?
Nonvisible radiation
 Infrared radiation
 Wavelengths are LONGER than red light
 Not VISIBLE, FELT as heat
 UV (ultraviolet) radiation
 Wavelengths SHORTER than violet light
 Causes sunburn, skin cancer, eye damage
Energy in the Atmosphere
 Sunlight must pass through the
ATMOSPHERE before reaching
Earth’s surface
 Some sunlight is absorbed or
reflected by the atmosphere
BEFORE it reaches the surface
25%
5%
 The rest passes through the
atmosphere to the surface
 What percent is reflected?
20%
 What percent is absorbed by
Earth’s surface?
50%
ENERGY
ABSORBED
 Ozone layer in the
STRATOSPHERE absorbs
most UV RADIATION
 Water vapor and carbon
dioxide absorb some
INFRARED RADIATION
 Clouds, dust, and other
gases absorb ENERGY
ENERGY
REFLECTED
 Some sunlight is
reflected. CLOUDS are
like mirrors and reflect
back into space.
 Dust particles and gases
reflect light in all
directions called
SCATTERING
WHY IS THE SKY BLUE?
 When you look at the sky, the light you see has been
SCATTERED around by gas molecules in the atmosphere.
 Gas molecules scatter the short blue wavelengths of visible
light more frequently than longer wavelengths.
 Scattered light therefore looks BLUER than ordinary
sunlight… sky = blue 
 Sunrise or sunset looks different because it passes through
a greater thickness of atmosphere. The scattering removes
more blue light and causes the sun to look RED.
BONUS QUESTION:
Why isn’t the sky blue in space?
Energy at Earth’s Surface
 Greenhouse
effect is the
process by
which gases
hold heat in
the air.
Checkpoint
1) The three types of radiation that Earth receives from the sun include
____________ ___________, _______________
________________, and _________________ _______________.
2) We can detect visible light because we can _________ it.
3) We can detect infrared radiation because we can _________ it.
4) Which form of radiation from the sun has the longest wavelength?
____________________ Which has the shortest?
___________________
5) Which color of visible light has the longest wavelength?
6) Which color of visible light has the longest wavelength?
7) Most of the sunlight that reaches Earth is _____________ by the
atmosphere or by Earth’s surface. (absorbed/reflected)
8) The sky is blue because those wavelengths are ______________ in
the atmosphere.
9) The energy from the sun that is absorbed by Earth’s surface
____________ the land and water. Most of it is then radiated back
into the atmosphere as _____________ _____________.
10)The process by which gases hold heat in the air is called the
_____________________ _________________.