Section 1.3Gases in the atmosphere absorb radiation

The atmosphere can affect light in four ways: Absorb light, reflect light, allow light to pass through, or

emit radiation. 99% of the Sun’s rays consist of visible light,

ultraviolet rays, and infrared rays (also known as heat).

We can not see ULTRAVIOLET RADIATION (more energy than visible light & causes sunburn and other types of damage) and INFRARED RADIATION (less energy than visible light & warms the materials that absorb it).

Gases and the Sun’s radiation

Ozone molecules (O3) are made up of three atoms of the element oxygen (different from O2, which your body uses). The ozone layer is found in the stratosphere.

The ozone layer protects life on Earth by absorbing harmful ultraviolet radiation from the Sun (which can cause skin cancer, sunburn, damage eyesight, and harm crops).

The ozone layer

The GREENHOUSE EFFECT occurs when gases in the atmosphere absorb and emit infrared radiation (keeping energy within the Earth’s system for a period of time).

Carbon dioxide, methane, water vapor, nitrous oxide, and other gases give off infrared radiation. These are known as GREENHOUSE GASES.

Without greenhouse gases, the infrared radiation emitted from the Earth’s surface would go back into outer space (making it too cold for life on Earth). Some infrared radiation is reflected but that which is absorbed keeps Earth warm.

The greenhouse effect