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Asked by emmagrace to Dalya, Derek, Sarah, Tim, Tom on 19 Jun 2011.
Question: How was radiation formed and used?
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Sarah Thomas answered on 17 Jun 2011:
Radiation is when a source gives out energy in the form of rays. There’s lots of different kinds of radiation: electromagnetc, x-ray, microwaves, and radiowaves. The difference between these types is the frequency of the radiation. Radiation is really useful and is used all the time for communication, medical purposes, and cooking!
Radiation can be formed in a number of ways. Here is how x-rays are made. Inside an x-ray machine is an x-ray tube. An electron gun inside the tube shoots high energy electrons at a target made of heavy atoms, such as tungsten. X-rays come out because of atomic processes induced by the energetic electrons shot at the target.
But there are certain types of radiation that are so strong they are react with our bodies can cause damage and these are called alpha rays, beta rays, neutron rays and gamma rays. Beta is more dangerous than Alpha, and gamma is the most dangerous of all. These harmful forms of radiation are typically formed by radioactive decay and nuclear fusion/fission.
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Tom Crick answered on 18 Jun 2011:
Matter and energy are never created or destroyed, they are transformed into different states; radiation comes in many different forms and can be created by matter changing to energy e.g. during nuclear fission. Two key properties for radiation are: ionisation and penetration: the more ionising the radiation is (for example, alpha radiation), the less penetrative it is, because it strips electrons off the matter it interacts with. More penetrative radiation (such as gamma radiation) is more dangerous, because it is harder to shield against (alpha radiation can be stopped by paper/thin aluminium, whereas strong gamma radiation needs thick lead!).
However, radiation also has a number of uses: X-rays in medicine, alpha and gamma radiation as cancer radiotherapy, etc. There are elements in nature that are naturally radioactive (e.g. Radon, Radium), but we have also created new radioactive elements that only have a lifetime of millionths of a second.
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Derek McKay-Bukowski answered on 19 Jun 2011:
Great answers from Tom and Sarah!
There are different ways of thinking about radiation. You can split it into “particle radiation” and “wave radiation” which is the mechanism by which the radiation moves. Or you can think of it as “ionising radiation” or “non-ionising radiation”, which is the effect that it causes when it hits something.
When people often talk about radiation, they are usually talking about “nuclear radiation”. Again, there are two ways that it is formed. One is the direct production of high energy particles and waves from the nuclear reaction itself. For example, a 236-Uranium atom splits into high energy particles, specifically 141-Barium, 92-Krypton and 3 neutrons. The energy from these particles is used to heat the water to make steam. The pressure from the steam is then used to drive turbines and thus generate electricity.
The problem is that some of the produced particles are not stable. They will “decay”, meaning that they will break down themselves. This is a random process and each individual nuclei will do it at different times. But on average, each type of nuclei will have a sort of average decay time — this is the half life.
When these nuclei decay, they also give off high-energy particles. This is a problem because once you have these nuclei, you can’t get rid of them easily. It is like having a fire that you can’t put out! When the nuclei decay, they fire off energetic particles, such as alpha or beta particles, which can be dangerous to human health.
Although many people don’t realise it, there is a lot of natural radiation too. A good example is 222-Radon, which can be found in many parts of the UK. Houses in some areas to prevent this radioactive gas from accumulating.
However, some of these are actually useful, and are used in medicine or scientific research. Generally, the quantities used are very small, but they still need to be handled carefully!
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