The electromagnetic spectrum - How colourful!



Firstly, an electromagnetic field is generated when charged particles are accelerated. All of these electrically charged particles are in the electric field and produce the magnetic field when in motion. The speed at which the particle is travelling determines the type of place it will take on the electromagnetic spectrum. The electromagnetic spectrum is a continuous range of wavelengths that occur on the electromagnetic field. the types of radiation that make up this chart have useful purposes for humanity but can also be damaging depending on their wavelength and frequency.


The order at which these waves go is like so;

-Radiowaves, these waves are the longest of any of the waves of the spectrum and because of this long wavelength the frequency is very low and not a lot of energy is stored. Radio waves can be as long as 100 km (62 miles)! and can have a frequency as low as 3kHz.

-Next is microwaves! These waves are still quite long and have low frequencies but do carry enough energy to heat your food in a microwave. Microwaves are about a metre long and have a frequency of 300MHz.


-Infrared is next being very useful for survival since it is the wave most frequently produced by any human. Infrared waves are usually 1 mm in size and have a frequency of about 300 GHz.


-Next is the one we all know and love visible light! Visible light is essential for our everyday experience of the universe because it allows us to views objects with little delay. There is no special reason why we are adapted to this part of the electromagnetic spectrum to see but it is very useful none the less! Visible light is 700 nanometres long and has a frequency of 770THz.

White light can be refracted into its colours through a prism, each of these colours has a different wavelength producing a different amount of energy that creates a different colour. The shorter the wavelength the more it is refracted so red light refracts the least because of its long wavelength nad violet is refracted the most because it is short.


-The ultimate tanner is next being the famous ultraviolet waves! These waves are let in by our atmosphere and allow us to get those beach bodies we desire. Ultraviolet waves are about 100nm and have a frequency of about 3PHz.


-If you ever broke a bone you have probably had one of these go through you, X-rays! X-rays are high-frequency waves that can be dangerous if not controlled. They have a wavelength of a tiny 1nm and a massive frequency of 3 EHz!


-Last but definitely not least Gamma rays! If you accidentally get hit by these you will be dead way before you turn into the hulk! Gamma rays have a wavelength of 1 pm and a frequency of 300EHz!


Uses of the waves


As radio waves are the longest they are good for communication because their long length allows them to travel far and bounce off the atmosphere to reach communication towers. Microwaves are good for cooking food because they are absorbed by the water molecules which heat up and cook the food. However, microwaves can only penetrate about 1cm into food so the outside is always hotter than the inside this is why you shouldn't cook meats in the microwave because they will be raw in the middle. Microwaves can pass through plastics and glass but are reflected by metals. So a metal barrier is inserted around the microwaves to stop waves getting out. If the waves did get out then it could be absorbed by the water in living tissue and cause damage. Microwaves are also used to communicate with phones. this is because their wavelength allows them to penetrate the atmosphere and be reflected off satellites. Phones use low energy microwaves to stop them being harmful to the body and there have been health concerns but no conclusive data has been reached.


Infrared radiation is given off by every object. because infrared to help spot things in the night because things that produce a lot of infrared radiation like humans can be seen clearer than buildings and the ground that produce little infrared radiation. Infrared radiation is also used in television remotes, they send pulses of infrared radiation to a sensor in the television that has a unique pattern to tell the television what to do.


Visible light is the way we communicate with the world and has been very useful for our existence. A theory for why we are able to see this part of the spectrum could be that our latest ancestors were sea creatures. Light refracts in the water into the different colours we see and the sea is supposedly where eyes were first evolved from so that could be why we see the colours that we do.


Ultraviolet radiation is found naturally in sunlight, we can't see of feeling this wave but the melanin in the skin reacts with it turning darker. This sensation is called tanning and it's when the pigment in the skin gets darker to stop the UV rays damaging cells. However, if the UV rays do get in the damaged tissue could turn cancerous and that is why tanning beds and spending long times in the sun increase cancer risk.


X-rays enable us to see into things that can't be witnessed without damaging the object such as the inside of humans and the contents of items. X-rays work because some objects like skin don't absorb the radiation but other objects like bone do which allows us to see in the body and find out what's happening inside because the bone will come out white and the skin will not show.


Gamma rays are a very high frequency that is part of the ionising wave group that take or add electrons to atoms. By changing the structure of the atoms and having a high energy wave can lead to deadly conditions such as cancer because the DNA is damaged and then changed. However, because of this power scientists have used it to sterilise equipment by killing bacteria on them. Alos they have been used to kill cancer cells by concentrating the high energy beam on cancer which kills it.