Nishant Pradhan
Grade 9
The Electromagnetic Spectrum!
The electromagnetic spectrum is a range of possible frequencies. Frequencies can be either high, or low. The EMS can be compared to a regular piano, where notes get higher as the keys move towards the right. All electromagnetic waves travel at the speed of light and can cross a vacuum.
There are seven types of waves in the EMS:
· Radio
· Micro
· Infra-red
· Visible light
· Ultra Violet
· X-ray
· Gamma Rays
Radio Waves:
They are caused due to different types of “transmitter” and are given off by various things, such as stars or colliding clouds during a thunderstorm. It is the first wave in the electromagnetic spectrum and is placed in the complete left due to its low frequency.
Uses:
The main use for this wave is for communication means. The different types of radio waves have different uses due to their respective wavelengths. For example, a long wave (wavelength 1-2km) is usually used by FM radio channels. Yet, a UHF [Ultra high frequency wave, length 1-2m] wave is used for aircraft radios.
Dangers:
Many believe that low frequency waves can cause multiple diseases, such as leukaemia and cancer. Many also feel motion sickness from low frequency waves.
Micro Waves:
Microwaves are basically high frequency radio waves, again caused by “transmitter”. They are used by mobile phones. They are after radio waves, moving towards the right.
Uses:
Cell phones work due to micro waves. But a problem with micro waves in phones is the need for many radio towers nearby because of the lack of range of these waves. Micro waves are also used to cook food and also used by the traffic police in the speed cameras.
Dangers:
Micro waves are known to cause “cataracts” in the eye [clouding]. Surveys also suggest that using cell phones too much can affect parts of your brain. So for safety, keep them calls short!
Infra red [IR]:
Next in the electromagnetic spectrum is infra red. They are “below” visible red lights. They are given off usually by warm objects, ex: stars, lamps ad fires.
Uses:
They are used for many tasks, such as in TV remotes and video recorders. Doctors also use heat lamps to heal sports injuries. Some alarm systems also have infra red sensors within them.
Danger:
OVERHEATING!
Visible light:
The only part of the EMS that our eyes can detect is visible light. Anything that is hot enough to glow gives off visible light. The white light we see is actually made up of a mix of colours.
Uses:
The most important use is the ability to see things.
Dangers:
Too much light can damage the retina.
Ultraviolet Rays:
It is made by special lamps to attract insects. The sun also gives off large quantities of it.
Uses:
UV rays are very useful. Their uses can be something simple from getting a sun tan to detecting forged blank notes. UV rays can also make your clothes glow. Hospitals use UV ray lamps to kill harmful microbes.
Damages:
They can cause serious damage to the retina. UV rays can also cause sunburn, and on occasion, even skin cancer.
X-Rays:
They are very high frequency waves and carry lost of energy. They are given off by stars and heavy quantities by nebulae. X-ray machines work be sending large amounts of electrons into towards the target, creating an image.
Uses:
Doctors use to “see inside people.” For example, when people break bones, x-rays help doctors analyze the injured area. They are also used in airport security checks to look through peoples luggage.
Dangers:
They can cause skin cancer and even brain damage.
Gamma Rays:
These are extremely high frequency waves and given off by radioactive substances.
Uses:
They are used to kill most cancer cells. This process is called Radiotherapy.
Dangers:
Due to its high frequency, gamma rays can cause immense amounts of cell damage. Mutations in growing tissues are also a big issue and can put unborn babies at a risk.