Section 2.1 Science Energy in Earth's Atmosphere

radiation

the direct transfer of energy by electromagnetic waves.

Which form of radiation from the sun has the shortest wavelength?

ultraviolet radiation

electromagnetic wave

Waves that transfer electric and magnetic energy through the vacuum of space.

When the Earth's surface is heated, it radiates most of the energy back into the atmosphere as which type of radiation?

infrared

Which form of radiation from the sun has the longest wavelength?

infrared radiation

List 3 forms of radiation from the sun

1) visible light, 2) infrared radiation, 3) ultraviolet radiation

What percentage of incoming sunlight is absorbed ny gases and particles in the atmosphere?

20%

What percentage of incoming sunlight is reflected by clouds, dust, and gases in the atmosphere?

25%

scatterings

reflection of light in all directions

What percentage of incoming sunlight is reflected by the surface back into the atmosphere?

5%

ultraviolet radiation

Electromagnetic waves with wavelengths that are SHORTER than visible light but longer than x-rays.

Why are sunsets red?

Gas molecules scatter short wavelengths of visible light (blue and violet) more than long wavelengths (red and orange). Scattered light therefore looks bluer than ordinary sunlight.

What happens to most sunlight that reaches Earth?

It is absorbed by the earth's surface to heat land and water

In what forms does energy from the sun travel to Earth?

Most of the energy from the sun travels to Earth in the form of visible light and infrared radiation. A small amount arrives as ultraviolet radiation.

Where does this heat come from?

Nearly all the energy in Earth's atmosphere comes from the sun.

How might conditions on Earth be different without the greenhouse effect?

Over time, the amount of energy absorbed by the atmosphere and Earth's surface is in balance with the amount of energy radiated into space. In this way, Earth's average temperatures remain fairly constant. However, as you will learn later, emissions from human activities may be altering this process.

What happens to the energy from the sun that is absorbed by Earth's surface?

Some of the sun's energy reaches Earth's surface and is reflected back into the atmosphere. About half of the sun's energy, however, is absorbed by the land and water and changed into heat

What happens to the sun's energy when it reaches Earth?

Some sunlight is absorbed or reflected by the atmosphere before it can reach the surface. The rest passes through the atmosphere to the surface.

greenhouse effect

process by which heat is trapped in the atmosphere by gases that form a "blanket" around the Earth

infrared radiation

wavelengths that are longer than red light. Infrared radiation is not visible, but can be felt as heat