Types of Electromagnetic Waves

There are many different forms of electromagnetic radiation (light) which differ in wavelength and frequency, but travel at the same speed. The different types of electromagnetic radiation listed at Electromagnetic Radiation, from Wikipedia the free encyclopedia are arranged according to increasing frequency as follows: radio waves, microwaves, infrared waves, visible light, ultraviolet light, x-rays, and gamma rays. All of these forms of light are emitted by the Sun.

Two low frequency light waves include radio waves and microwaves .Radio waves are harmless. They are all over the atmosphere. These waves are converted to sound by a radio. Microwaves are a type of light used to cook your food!

Infrared light is associated with heat. Infrared light is all over the Earth. It is emitted any time an object gives off heat. Therefore, it is impractical to use infrared telescopes on the Earth to view space. There would be a lot of interference from the ground. Pit vipers use infrared light to sense prey. The hotter regions associated with infrared light are red and the cooler regions are blue. The military also uses infrared goggles as night vision to detect enemy personnel. The police use infrared cameras to catch fleeing criminals.

Visible light forms the colors of the rainbow. The colors of the rainbow can be summarized by the acronym, ROY G BIV : where R=Red, O= Orange, Y=Yellow, G=Green, B=Blue, I=Indigo, and V= Violet. The Sun gives off white light. The white light is split when bending through a raindrop into its constituent colors. Visible light is the light we see. A green object reflects the color green, and a red objects reflects the color red.

The visible light from the stars takes a long time to reach the Earth. So, the stars you see in the night sky may not even exist anymore, because you always see their past image. When you look at anything; you always see it in the past. This is because it takes time for light to travel from one object to another.

Ultraviolet light travels from the Sun to the Earth. It even passes through clouds. That's why you can get a tan on a cloudy day! Ultraviolet light has high energy and is harmful. It can cause DNA damage to cells, resulting in skin cancer. The skin protects itself to an extent by generating melanin. Individuals who are lighter skinned are more likely to get skin cancer than those that have darker skin.

X-rays are emitted by stars and other devices such as X-ray machines. They do not penetrate the Earth's atmosphere. X-rays have more energy than UV light, and therefore are more harmful. X-rays can pass through any metal except lead. That's why the dentist places a lead vest over you when taking x-rays. This is to prevent x-ray penetration to organs. X-rays can penetrate the skin to reveal abnormalities in the human body.

Gamma rays are the most harmful of the light forms. They have the highest frequency and energy. Gamma rays are emitted by the Sun, but do not penetrate the Earth's atmosphere. Gamma rays are emitted in an atomic explosion. Reptiles have some resistance to this form of radiation, because of their scales.

All the electromagnetic waves have the same speed, but differ in frequency and wavelength. The differences between the waves give them specific characteristics.

Source

Electromagnetic Radiation, from Wikipedia the free encyclopedia, Wikipedia