If radiation collides with molecules in the air or in your body, it throws out of them electrons. By throwing out electrons you produce charged particles called ions. This means it is the radiation responsible for ionising molecules.
If this happens in our body, the cells may die or they may undergo a change called a mutation. The result is called radiation sickness. A large dose of radiation will cause death!
Small doses of radiation over a long period of time can cause the cells to multiply. However, these cells are mutated. Some time later cancer may occur.
We are surrounded by background radiation all of the time! Background radiation comes from the soil, rocks, the air, water, plants, building materials and food. Some radiation is due to cosmic rays from outer space. However, fortunately, our body can withstand low level radiation without ill effects because it is able to repair any damage.
As we've seen from the above narrative, radiation can be harmful, even cause death. However, it can also be most helpful.
Gamma rays are capable of passing deep inside the body and damage cells on their travels. But as well as causing cancer, they can be used to kill off cancer cells and even cure people from this illness. This treatment is called radiotherapy. Cobalt-60 is commonly used to kill cancer cells. The idea is to aim accurately at these cells with the correct strength.
Gamma rays successfully kill microbes that cause food to decay. So food treated with this radiation have a longer shelf life. Surgical instruments and syringes are also treated with gamma rays, in order, to prevent infections been transferred from patient to patient.
A Geiger Counter is an instrument that measures radiation. If radioisotopes are added to oil or gas, engineers can follow the radioisotope, and trace any leaks in oil or gas pipes.
When an animal or plant dies it stops taking in carbon. But its carbon-14 content continues to decay. If we compare the carbon-14 with that from a living thing, and knowing the half-life of carbon-14, the age of animal and plant remains can be calculated. This is known as carbon dating.
Twelve out of every 1000 potassium atoms is the radioistope potassium-40. Its half life is a staggering twelve thousand years and decays to eventually form the stable argon atom. By measuring the argon content of many rocks that contain potassium, scientists can calculate the age of the rock.