Published byAlexandrina Walker Modified over 8 years ago
Chapter 7 Section 4 Energy in Earth’s Atmosphere
Standards and Objectives
S 6.3d: Students know heat energy is also transferred between objects by radiation. ( radiation can travel through space). S 6.4.b: Students know solar energy reaches earth through radiation, mostly in the form of visible light. Students will be able to: State in what form energy travels from the Sun to the Earth Explain what happens to the sun’s energy in the atmosphere and at Earth’s surface.
Language of the Discipline
electromagnetic waves radiation infrared radiation ultraviolet radiation scattering greenhouse effect
Energy from the Sun (Input)
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. Electromagnetic waves are classified according to wavelength, or distance between waves. Radiation- the direct transfer of energy by electromagnetic waves, so the electromagnetic waves given off by the sun are called solar radiation.
Energy From the Sun ( cont.)
Most of the energy from the sun travels to Earth in the form of visible light. Visible light includes all the colors you see in a rainbow. The different colors are the result of different wavelengths. Red and orange have the longest wavelengths, while blue and violet light have the shortest wavelengths.
Energy From the Sun ( cont.)
Infrared radiation- a form of electromagnetic energy that has wavelengths that are longer than red light. Infrared radiation is not visible, but can be felt as heat. Ultraviolet radiation- an invisible form of energy with wavelengths that are shorter than violet light. The sun gives off ultraviolet radiation. It can cause sunburns, skin cancer and eye damage.
Solar radiation includes a full spectrum of wavelengths, from below the infrared to above the ultraviolet.
Energy in the Atmosphere
Scattering- a process by which dust particles and gases in the atmosphere reflect light in all directions. When you look at the sky, the light you see has been scattered by gas molecules in the atmosphere. They scatter short wavelengths of visible light ( blue and violet) more than long wave-lengths (red and orange). Therefore, scattered light looks looks bluer than ordinary sunlight. This is why the daytime sky looks blue.
Energy at Earth’s Surface
Greenhouse effect- the process by which gases hold heat in the air It is a natural process that keeps Earth’s atmosphere at a temperature that is comfortable for most living things.
Checking for Understanding
True of False? Visible light includes all the colors that you seen in a rainbow? Answer: TRUE
Dust particles and gases in the atmosphere reflect light in all directions, a process called ____________. Answer: Scattering
The process by which gases hold heat in the air is call the __________ ______________.
Answer: Greenhouse effect
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