Electromagnetic radiation:

Wave motion:
The transfer of energy without matter is called wave motion. There are two types of waves that can transfer energy. The particles of a transverse wave, such as a wave at the beach vibrate at right angles to the direction of motion of the wave. In a longitudinal wave, such as a sound wave, the particles vibrate backward and forwards in the same direction as that of the wave

Transverse wave:
A wave which its particles vibrate at right angles to the direction of the motion of the wave

Longitudinal wave:
A wave in which its particles vibrate in the same direction as the wave itself

Wave properties:
The number of waves produced each second is called frequency of the wave. Wavelength is the distance between two successive waves. It is represented by the Greek symbol lambda and is measured by metres. The wavelength of some radio waves is several kilometres, whereas the wavelength of visible light is less than one thousandth of a millimetre. The amplitude of a wave is the maximum distance it extends beyond its middle position

Electromagnetic spectrum:
The entire range of frequencies of electromagnetic radiation that can be produced is called electromagnetic spectrum. This ranges from low-energy radiation, such as radio waves, through high-energy gamma radiation. As the energy of the radiation increases, the frequency of the electromagnetic waves increases and the wavelength decreases

Highest to lowest energy:
* Gamma rays
* X-rays
* Ultraviolet rays
* Visible light
* Infrared rays
* Microwaves
* Radio waves

Gamma rays
Gamma rays have a wavelength of about one-hundred-billionth of a metre. Gamma rays are produced in making nuclear power and nuclear bombs, and can be detected with photographic film or a machine called a Geiger counter. Gamma rays can free electrons from their atoms by removing these electrons from surrounding atoms

X-rays
X-ray radiation has such a high-energy that it can damage cells and tissues an also the genetic material inside cells

Ultraviolet rays/light

Sunlight contains ultraviolet light in addition to infrared and visible light. Ultraviolet light is radiation with s higher frequency than violet light (ultra means beyond)

Visible light
Visible light is from the sun and it helps us to make sense of our world, and is also essential for much of the life on Earth. Plants absorb light and use the energy to make carbohydrates, fats, protiens and other materials that humans and other animals depend on. Visible light (white light) consists of different colours. You can see all these different colours when you view the rainbow. Each colour has a different wavelength and frequency. Blue light has the shortest wavelength and the highest frequency while red light has the longest wavelength and the lowest frequency

Infrared radiation/rays
Heat is transfered from the sun to us as infrared radiation. Infrared rays are given this name not because they are red, but because they are next to red light in the visible spectrum. 'Infra' means below and infrared light/radiation has a lower frequency than red light. You cannot see this radiation, but you can detect its presence as warmth on your skin. The hotter somethig is, the more infrared radiation it emits

Microwaves
Microwaves have shorter wavelengths than radio waves. Shorter microwave with wavelengths of about 0.1mm. Microwaves are absorbed by water, fats and sugars of food, causing food molecules to vibrate and heat up. Because the heating occurs insde the food, causing the foods molecules to vibrate and heat up. Glass, paper and many plastics don't absorb microwaves, and metal reflected microwaves

Radio waves (short wave radio and long wave radio
Radio waves are produced through vibrating or oscillating electrons in a trasmitting aerial. Radio waves have the longest wavelengths of all types of electromagnetic radiation. This can range from a few metres to a few kilometres in length. As a result, these are the lowest-energy form of electromagnetic radiation. Radio waves can travel large distances. They make electrons in the atenna of a television or radio vibrate, and this is converted into the sounds or images you see and hear when tuning in

Short wave and long wave radio signals are different types of radio waves. Short wave radio signals (wavelength about 30m) can be transmitted long distances by beaming the waves upwards at an angel. The waves are deflected back to Earth by a layer of the atmosphere called the ionosphere, far away from where the transmitter is located

Long radio waves are used for communication because they bend around the Earth's surface when transmitted

Am and Fm radio
Am and Fm radio waves involved by using a wave called a carrier wave. An Fm signal has a wavelength of around 3m, where as an Am signal has wavelengths longer than 100m. Am radio waves can bend around large obstacles like buildings, trees and hills (easier than Fm waves)

	Created by Jordyn Niu almost 9 years ago

Note on Electromagnetic Radiation, created by Jordyn Niu on 17/11/2015.