Which rays matter?
Most of the Sun's energy comes in three kinds.
Sorting the Sun's rays
The Sun sends out many kinds of EM waves, from gamma rays to radio waves.
Do all kinds reach the Earth in large amounts?
What this lesson covers
The idea
About 99% of the Sun's energy reaching the Earth is ultraviolet, visible and infrared radiation; gamma rays and X-rays are mostly filtered by the upper atmosphere, and microwaves and radio waves carry too little energy to warm it.
Sorting the Sun's rays
The Sun sends out many kinds of EM waves, from gamma rays to radio waves.
Do all kinds reach the Earth in large amounts?
- No, three regions give most energy
- Yes, equal amounts of each
- Radio waves give most energy
Sort the radiation
Put each kind of radiation in its group.
Three regions shape the climate
UV, visible light and infrared together carry about 99 per cent of the Sun's energy, and they shape the Earth's climate and support life. The other kinds are held back or are too weak to matter for heating.
About 99% of the Sun's energy falls in the ultraviolet, visible and infrared regions. Gamma rays and X-rays are mostly filtered by the upper atmosphere, and microwaves and radio waves carry too little energy to warm the Earth.
Notes
About 99% of the Sun's energy is UV, visible and infrared. Gamma rays and X-rays are mostly filtered out, and microwaves and radio waves carry little energy.
Check yourself
About how much of the Sun's energy falls in the UV, visible and infrared regions?
What mostly stops gamma rays and X-rays from reaching the Earth?
Why do microwaves and radio waves not warm the Earth much?
Which three regions shape the Earth's climate and support life?
- About 50 per cent. The book says about 99 per cent of the Sun's energy falls in these three regions.
- About 1 per cent. The book says about 99 per cent falls in these regions, not 1 per cent.
- About 99 per cent — correct. Yes!
- The Earth's upper atmosphere filters them — correct. Yes!
- They carry too little energy. This is said of microwaves and radio waves. Gamma rays and X-rays have very high energy.
- The ocean absorbs them before they arrive. The chapter says the upper atmosphere mostly filters gamma rays and X-rays.
- The upper atmosphere filters them out. The chapter says that about gamma rays and X-rays. Microwaves and radio waves simply carry very little energy.
- They carry very little energy — correct. Yes!
- They are the same as visible light. Visible light is one of the three main regions. Microwaves and radio waves carry very little energy.
- Gamma rays, X-rays and ultraviolet. Gamma rays and X-rays are mostly filtered by the upper atmosphere.
- Microwaves, radio waves and visible. Microwaves and radio waves carry very little energy to warm the Earth.
- Ultraviolet, visible and infrared — correct. Yes!