Electromagnetic Waves

By Kate Morris

The Disturbance That Creates The Wave

Electromagnetic waves are formed by the vibrations of the electric and magnetic fields. These fields are perpendicular to the direction the wave is traveling. The two fields come together to create this wave. Once formed, the energy travels at the speed of light until further interaction with matter.

Differences Between EM & Mechanical waves

Electromagnetic waves can transport energy through a vacuum. That basically means that EM waves can transport through an empty space. Mechanical waves require a medium in order to transport energy. Also, electromagnetic waves contain two parts - the electric part and the magnetic part. While, mechanical waves contain only one part.

Radio Waves

Radio waves have the longest wavelength and the lowest frequency. These two characteristics go hand and hand. They are the longest waves, therefore they have the lowest energy and are associated with the lowest temperatures. Radios capture radio waves that are released by radio stations. Radio waves are also released by stars and gases in space. Radio waves are mainly used for television signals and for the music on the radio.

Microwaves

Microwaves have low frequencies and long wavelengths. These radiations are even lower and longer than visible light. Certain microwave radiation wavelengths pass through the Earth's atmosphere and can be used to transmit information to and from satellites in orbit. Microwaves are mainly used for cooking with microwaves and communications through cell phone calls.

Infrared

Infrared radiation is what we feel as heat and is absorbed by skin. These radiation wavelengths can span anywhere from 710 nm to 1 millimeter. Infrared radiation has also slightly lower frequencies and longer wavelengths than visible light. The main use of infrared radiation is optical fibre communication and television remote controls.

Visible Light

Visible light is right in the middle of the spectrum showing that it has a average frequency and wavelength. Visible light is detected by the human eye. These radiation wavelengths cover the range from 400 to 700 nm. The main use of visible light is seeing. In a normal day, light bulbs and stars are examples of things that emit visible light.

Ultra-violet

Ultra-violet radiation is found naturally in sunlight. Although, we can't see or feel ultra-violet radiation, our skin responds to it by turning darker. This is the reason why our skin burns and tans. The wavelengths can be from 10 – 310 nm. Ultra-violet radiation is used in sun beds, security pens, and florescent lighting.

X-ray

X-ray radiations have fairly high frequencies and short wavelengths. They can't be seen or felt. X-ray radiation wavelengths range from 0.01 – 10 nm. X-rays can pass through skin and soft tissue, but do not easily pass through bone or metal. Today, dentists use x-rays to get an image of the teeth and security at airports use them to see through the luggage.

Gamma Ray

Gamma rays have the shortest wavelengths and very high frequencies. They have wavelengths of less than 0.01 nanometers. These also cannot be seen or felt. They mostly pass through skin and soft tissue, but some of it is absorbed by cells. Gamma rays can be used to sterilize surgical instruments, kill harmful bacteria in food, and kill cancer cells. Also, doctors use gamma ray imaging to see inside the body. The biggest gamma ray generator there is is the Universe.
The Electromagnetic Spectrum