Because of there power to penetrate through things they are good for viewing earth from space.
Microwaves can be created by making electrons move around in a small metal box with no air. This is called a magnetron; all microwave ovens have a magnetron to produce the microwaves used for cooking.
Microwaves can be dangerous though if misused, they can damage living cells.
Infrared waves lie between visible light and microwaves in the electromagnetic spectrum. Infrared light has a range of wave lengths, it rangers from “near infrared “to “far infrared”.
Near infrared light is the closes to visible light and far infrared is closer to the microwaves. The longest infrared wave is the size of a pinhead and the smallest near infrared are the size of cells, they are microscopic.
Infrared waves are thermal; we experience this infrared radiation everyday in the form of heat from, the sun, a fire, and radiator.
Infrared is sometimes know as radiant heat or thermal radiation, so any object that has a temperature radiates in the infrared even objects that are very cold like an ice cube, emits infrared. When an object is not quite hot enough to radiate visible light, it will emit most of its energy in infrared. For instance, charcoal may not give of light but it does emit infrared radiation that we feel as heat, the warmer the object gets the more infrared radiation it gives off.
Humans at normal body temperature radiate strong infrared radiation. As you can see from the diagram below, the orange shows the hottest parts of his body and the blue area the coldest.
This picture was taken using a special camera and film, which detect temperature
Infrared light can also be sent down optical fibres for television cable and telephone links.
This part of the electromagnetic spectrum we can see and it is the smallest part. The colours of the visible spectrum are RED, ORANGE,YELLOW,GREEN,BLUE,INDIGO and VIOLET. Each colour has a different wavelength and frequency, Red has the longest and VIOLET the shortest. When all the waves are seen together, they appear as a white line. When the white light shines through a prism or through water vapour, the white light is broken apart into the colours of the visible light. Both ultra violet and infrared are visible with the human eye. Cones in our eyes are receivers of tiny light waves. The sun is a natural source of visible light waves and our eyes see the reflection of sun light off objects around us.
Some examples of visible light can be found in television tubes, neon lights and even in some insects such as the glowworm.
These waves have a very high energy and very short wave lenghth, shorter than visible light. They are invisible to the human eye.
This part of the spectrum can be divided into 3 regions
- NEAR ULTRAVIOLET
- FAR ULTRAVIOLAT
- EXTREME ULTRAVIOLET
The regions are distinguished by how energetic the ultraviolet radiation is and by the wavelength.
The near ultraviolet light is the closest to visible light and the extreme ultraviolet light is the closest to x-ray and is the most energetic of the 3.our sun omits light in different ways and wavelengths it is the ultraviolet rays from the sun that cause sunburn and skin cancer.
Certain chemicals glow when they are exposed to ultraviolet light.
X-rays have so much energy and such short wave lengths; they can go right through you without you feeling a thing. They are most commonly used in medicine to detect broken bones. I will go into more detail in task 2, when I talk about how the electro magnetic spectrum relates to medicine.
X-rays act more like a particle than a wave and are highly penetrative. Over exposure to x-rays can cause cancer. This is why the radiographer wears a lead apron and stands behind a screen.
These are very penetrating waves, even more so than x-rays, which are emitted by some radioactive materials. They can travel unlimited distances through air. They do not hit many atoms and they travel through material with ease. Gamma rays carry no charge and therefore are unaffected by magnetic and electric fields.
Gamma rays have the highest frequencies of all electromagnetic waves.
Radioactive substances like cobalt and caesium emit gamma radiation. We are still discovering more about gamma rays but they are still the most unknown of the waves in the spectrum.
TASK 3.
The electromagnetic spectrum is widely used in the world of medicine today. It is responsible for curing many illnesses such as cancer and is used in the detection of many medical conditions such as broken bones.
The ones I will be looking at more closely are radio waves, infared, visible light, ultra violet-rays and gamma rays.
Radio waves are used primarily in MRI scanners.MRI stands for magnetic resonance imaging, it has been used since the begging of the 80s.the MRI scanner uses magnetic radio waves, it makes it possible to detect and take pictures of almost all the tissues in the body. the parts of the body such as bone come out dark because they contain the least hydrogen atoms, but fatty tissue for example contain lots of hydrogen atoms so it is a much brighter image.
The scanner works by, Paitents lying inside a large cylinder, radio waves 10,000 to 30,000 times stronger than the magnetic field of the earth are sent through the body. This affects the body’s atoms, forcing the nuclei into different positions. As they move back into place, they send out radio waves of there own. The scanner then picks up these waves and the computer attached to the scanner turns then into pictures.
The benefits of using radio waves are there are no known side affects and the tests are not painful.
Hot objects give off invisible heat-rays called infrared radiation. Special cameras, called thermo grams, can be used to take photographs. In medicine thermographs are used to show different temperatures .doctors have found that tumours are warmer than healthy tissues and show up clearly on a thermograph.
Physiotherapists also use infrared. They shine heat lamps on to affected areas on the body this heats up the muscle and tissues and helped to sped up healing. This is known as heat treatment.
Colour therapy is becoming increasingly popular, as a way of treating illness .There is no doubt that our body is aroused and energised by some colours, calmed and relaxed by others. Colours cab be healing and they can make you agitated and ill. The health of our internal organs are claimed to be ordered by the colour we expose ourselves to. Mentally and emotionally, colours work on a deep level, changing our moods and our sense of well being. Red is the longest wavelength we can see and has the slowest frequency and vibration. Its energy is passionate, warm and stimulating.violet has the shortest wavelength and the fastest vibration, it is calming, cooling and purifying. The pituitary gland is the most affected by colour; it produces substances that regulate hormones.
Some people have colour therapy .this is where different colours are shone on to them because there illness is due to an imbalance in there colours see below.
The benefits of this are some people belief in it because it is invasive and helps people with depression instead of taking drugs.
Ultra violet radiation is used to treat skin conditions; it is also used to sterilize equipment because it kills harmful bacteria. To much of it though can cause skin cancer as in sun light. Ultra violet light only gives temporary relief so when you stop the treatment you skin condition will return.
Ultra violet light is also used in incubators for premature babies who have jaundice. The ultra violet light increases the chemical in the body that reduces the condition.
Gamma rays are used by using radioactive substances as tracers. They put tracers inside patient’s bodies to see where the blockages are. Patients with lung problems can breathe in xenon-133 this is a gas that send our gamma rays.
Gamma rays are also used in the treatment of cancer, we call it radiotherapy, it is quite personal for me as I am at present undergoing some for bowel cancer, the gamer rays kill of all the cancer cell, the problem is they cannot distinguish between cancer cells and healthy cells so if the radiotherapy machine is not in the right place healthy cells will die to.
X-rays are the most common wave of the electromagnetic spectrum used in medicine. They are mainly used to detect broken bones. An x-ray is taken at the hospital using a special machine and film. The film is placed under the affected area and the x-ray is aimed from the top through you. Because your bones are very dense they absorb the x-ray, waves.x-rays can be harmful because they are extremely ionising.
A radio telescope consists of a radio receiver and an antenna system that is used to detect and radio frequency radiation from an extraterrestrial source. A radio telescope collects radiation in aperture or antenna, from this it becomes an electrical signal, a receiver called a radiometer transforms it. This signal is then amplified, and then recorded. radio telescope are used to look towards the heaven of the planets and comets, giant clouds of gas and dust, by studding the radio waves originating from theses sources astronomers can learn about composition, structure and motion.
Many astronomical objects emit radio waves.
Microwaves are used for deep space communications as well as for television, mobile phones and data communication networks, radar and satellites. Because microwaves can penetrate haze and light rain they a good for viewing the earth from space.
A microwave beam travels in a straight line, it can be reflected from a smooth surface and a lens can focus it.
In 1960 a discovery was made by accident, two scientist detected a background noise using a special low noise antenna; the noise came from every direction. The scientist realized they had discovered the cosmic microwave background radiation. This radiation, which fills the whole universe, is believed to be a clue of how if began know as the BIG BANG!!!!!!!
Infrared waves are emitted from objects in space such as planets and interstellar dust grains.studing the rays will allow astronomers to see through dust clouds that obscure the optical wavelength, the centre of the Milky Way can be seen in infrared; this is the biggest benefit of infrared.
There are some problems though most of the infrared wavelengths have trouble penetrating the earth’s atmosphere. This is because molecules in the air block the infrared light from space. The best location to infrared astronomy is the South Pole due to the fact it is so cold and therefore the temperature will not affect the infrared rays.
Gamma rays have the smallest wavelength therefore the most energy. They travel across the universe only to be absorbed into the earth’s atmosphere.
Gamma=rays are the most energetic forms of light and are produced by the hottest regions of the universe. They are also produced by such violent events as supernova explosions or destruction of atoms and less dramatic events like the decay of radioactive material in space. Things like supernova explosion (the way in which massive stars die), neutron stars and pulsars and black holes are all sources of celestial gamma rays.
Gamma-rays bursts can realise more energy in 10 seconds than the sun will emit in 10 billion years. so far all the gamma-rays observed have come from outside the milky way galaxy.sientist believe that gamma-ray burst occur every few million years here inside the milky way, by solving the mysteries of gamma-bursts we hope to gain further knowledge of the origins of the universe and the rats in which it is expanding.
The ultraviolet universe looks quite different from the stars in visible light. most stars are cool and their radiation is emitted in the visible light part of the electromagnetic spectrum.ultaviolet radiation is invisible therefore if helps us to view stars at their birth of death with out this light we would not know if the stars excisted.ulta violet is not really used in celestial space because the earths atmosphere blocks it.
I n the assignment I have gone in to detail about the electromagnetic spectrum and it uses both in medicine and in space.
I found it quite hard to find information for its uses in celestial objects.
I did find it very interesting and I have learnt a lot about it.
BOOKS
As in a week- Letts
Physics basic fact-Collins gem
Universal process-open university
Websites
