Electomagnetic Spectrum

By Lulu and Greta

What is it?

Within the electromagnetic spectrum there is a wide range of wavelengths and photon energies. Light used to "see" an object must have a wavelength around the same size as or smaller than the object.
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Radio Waves

Radio waves are produced by various types of transmitter. These waves are also given off by sparks, stars and lightning, this is why you can hear interference on your radio during a thunderstorm. Radio waves have the lowest frequencies of the electromagnetic waves and they are mainly used fore communication. A long wave has a 1 to 2 km in a wavelength. The first prediction of Radio Waves was a resulted of mathematical work performed in 1867 by Scottish mathematical physicist James Clerk Maxwell but in 1887, Heinrich Hertz demonstrated the reality of Maxwell's electromagnetic waves by experimentally generating radio waves.

Microwaves

Microwaves are created by cooking and communication methods.Microwaves are produced by various types of transmitter such as mobile phones, microwaves and satellites, mostly for cooking and communication techniques. Microwaves’ wavelengths range from one meter to one millimeter. In 1945 the heating effect of a microwave was accidentally discovered by Percy Spencer, an American engineer from Maine. He discovered this when he noticed that the microwaves he was producing started to melt a chocolate bar he had in his pocket.

Infa Red

Infa red rarities is below visible red light in the electromagnetic spectrum. Infa red is given off by hot objects: stars and lamps emit it. Infrared light was discovered in 1800 by Sir Frederick William Herschel. Herschel, born in Hanover, Germany. A typical wavelength will be 700 nanometers (nm) to 1 mm.

Ultra-Violet

Ultraviolet light has shorter wavelength than visible light. It cannot be seen by the human eye but it can be seen by some insects such as the bumblebee. Ultraviolet light was discovered in 1801 by Johann Ritter. The wavelength can range from 10nm to 400nm.

Visable light

Visible light is called like that becuase it is the only kind of wave us humans are able to see: colours. Visible light waves allow us to see the only colour an object does not absorb and so reflects. Visible light can also source from the water vapor in the atmosphere that breaks the wavelengths apart, creating a rainbow. Each color in a rainbow corresponds to a different wavelength. Violet, the colour with the shortest wavelength, is 380 nanometres long, whilst red, the colour with the longest wavelength, measures 700 nanometers.