To realise that knowledge about probabilities is vital for life decisions
[LO 5.1, 5.5]
RISKS
In life we often take certain risks – in fact, life is full of risks. We can’t avoid taking risks, but if we know how big the risks are, then we can avoid the bad ones. The study of risks is very difficult, but we can make some simple, wise choices if we understand the basics.
Let’s look at some risks everyone is exposed to. This is only a small number of many, many daily risks.
1. Radiation can cause cancer. If all the little bits of radiation you are exposed to from day to day add up to enough, you have a greater
risk of getting cancer. Where does radiation come from?
- There is natural radiation – it is all around us – from space and from the earth. Where you live makes a big difference. Radon is a radioactive gas that seeps out of rocks and gets trapped in houses. If you want to know how big your exposure is, then the radon in your house can be tested. Making sure that stale air in a house gets removed, is a good way to get rid of radon, even if you don’t know how much there was
- Weapons are another source of radiation – think of the atom bombs dropped on Japan at the end of the Second World War. Many people died then from the explosion itself, and many died from the radiation a little later – but even now people who were e
x posed to the radiation are getting cancer
- Accidents at nuclear power stations usually cause some radiation to be emitted. People who come into contact with radiation in such an accident, are at risk of dying or getting cancer later.
- Ordinary medical
x- rays do not add a great deal to the radiation you are e
x posed to. But it is sensible not to have
x- rays for little reason, or too often. Just after
x- rays were discovered, they were a great novelty and
x- rays were taken just for the fun of it, or for trivial reasons. Now we are horrified at the thought that people could have been so careless – but they did not know any better.
2 Travel is a great source of risk. Accidents can, and do, happen frequently. But the risk varies greatly with the type of transport you choose. Passenger aircraft are very safe, while personal motorcars are much more risky. The way these risks are usually calculated is to divide the number of people dying in a certain period by the total number of kilometres each person travelled, times the total number of people travelling. This ratio is called deaths per person-kilometre. This number is higher for passenger cars than for passenger aircraft, that is why we say that travelling by air is safer than travelling by car.
- Many people believe that air travel is very dangerous. One of the reasons for this is that an aircraft accident can cause many deaths, but normally a car accident claims few lives. But one has to remember that there are few air accidents, but people die in car crashes daily. This is why the deaths per person-kilometre is a good way to compare them. By the way, bikers on motorbikes even more unsafe than motorists.
- If you want to have your car insured, then the insurance company takes these figures very seriously. They also know that people in certain age groups are more at risk, and that is why they have higher premiums for young males than for old ladies.
