Chapter 1 – Earth’s Chapter 1 – Earth’s Changing AtmosphereChanging Atmosphere

Section 1.3 – Section 1.3 – Gases in the Gases in the atmosphere absorb atmosphere absorb

radiationradiation

ObjectivesObjectives•BEFORE, you learnedBEFORE, you learned

• • Solar radiation heats Earth’s surface and atmosphereSolar radiation heats Earth’s surface and atmosphere• • Earth’s surface and atmosphere give off radiationEarth’s surface and atmosphere give off radiation• • The ozone layer is in the stratosphereThe ozone layer is in the stratosphere

•NOW, you will learnNOW, you will learn• • More about how radiation and gases affect each More about how radiation and gases affect each otherother• • About the ozone layer and ultraviolet radiationAbout the ozone layer and ultraviolet radiation• • About the greenhouse effectAbout the greenhouse effect

• The atmosphere can affect light in The atmosphere can affect light in four waysfour ways

– It can It can absorbabsorb light light– It can It can reflectreflect light light– It can let It can let lightlight pass through pass through– It can It can emitemit (give off) light (give off) light

  

I. Gases can absorb and give I. Gases can absorb and give off radiationoff radiation

• There are forms of radiation humans cannot There are forms of radiation humans cannot seesee– Visible light – Visible light – light that we are able to see with our naked light that we are able to see with our naked

eye, made up of the 7 colors ROY G BIV = white light eye, made up of the 7 colors ROY G BIV = white light – Ultraviolet radiation – Ultraviolet radiation – waves that have more energy than waves that have more energy than

visible light (higher frequency)visible light (higher frequency)– Ultraviolet radiation can cause Ultraviolet radiation can cause sunburn, skin cancer, sunburn, skin cancer,

damage to your eyesight, paint, plastic, harm crops, etcdamage to your eyesight, paint, plastic, harm crops, etc– Infrared radiation – Infrared radiation – waves that have less energy than waves that have less energy than

visible light (lower frequency)visible light (lower frequency)– Infrared radiation Infrared radiation usually warms the materials that absorb usually warms the materials that absorb

it it – Electromagnetic Spectrum – Electromagnetic Spectrum – everything from what we can everything from what we can

to what we cannot see. It includes UV rays, X-rays, to what we cannot see. It includes UV rays, X-rays, Microwaves, Gamma rays, TV/radio waves and visible Microwaves, Gamma rays, TV/radio waves and visible lightlight

II. The ozone layer protects II. The ozone layer protects life from harmful radiationlife from harmful radiation

• Ozone – is made up of 3 atoms of the oxygen element

• The ozone protects life by absorbing harmful UV rays from the sun

• The ozone layer is located in the second layer (stratosphere)

III. The greenhouse effect III. The greenhouse effect keeps Earth warm.keeps Earth warm.• The Greenhouse effect is The Greenhouse effect is gases that absorb and gases that absorb and

emit infrared radiation, which keeps energy in emit infrared radiation, which keeps energy in Earth’s system for a while Earth’s system for a while

• Greenhouse gases give off Greenhouse gases give off infrared radiation infrared radiation • Examples of greenhouse gases: Examples of greenhouse gases: carbon dioxide, carbon dioxide,

methane, water vapor, nitrous oxide, and other methane, water vapor, nitrous oxide, and other gases that absorb and give off infrared radiation gases that absorb and give off infrared radiation

• If the atmosphere had no greenhouse gases, If the atmosphere had no greenhouse gases, Earth temperature would only be Earth temperature would only be -18 degrees C/ -18 degrees C/ 0 degrees F0 degrees F

• Atmosphere without Atmosphere without Greenhouse Gases Greenhouse Gases

• - infrared radiation - infrared radiation would go straight would go straight through to outer spacethrough to outer space

• - water freezes and - water freezes and too cold for most too cold for most forms of life on Earth forms of life on Earth to surviveto survive

• Atmosphere with Greenhouse Gases

• infrared radiation is kept within our atmosphere

• - - water stays in liquid form