Radioactivity explained to children

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All matter around us, water, air, earth… we are made of small grains, very small grains called “atoms”. There are 92 different kinds altogether. As with Lego blocks, everything in the universe, from stars to us, is “manufactured” from these 92 atoms. There are other man-made atoms.

Each atom has a name: the number 1, which is the smallest, is called “hydrogen” and No. 92, which is heaviest in nature, “uranium.” In between, there are certainly names that you know, like oxygen, gold, iron … Two hydrogen atoms attached to an oxygen atom form a small block that is water.

But I digress. Some of these atoms are said to be “radioactive.” Like a cannon, they can fire a small shell even smaller than the atom itself. These small shells are dangerous because they can penetrate the human body as when you go to an X-ray.

In a nuclear reactor, there are a lot of radioactive atoms that fire shells. That is why they are locked in a vault called “containment.” The problem at the Fukushima plant is that the radioactive atoms escape into the water and in air. Some fall near the plant, others are carried by winds around the Earth.

A radioactive atom has no target. If it is next to us, it is likely that the shells go away. But if you eat contaminated vegetables, drink polluted water or breathe air polluted by radioactive atoms, the shells fired by the atoms in the body will do damage every time!

Obviously, there are many more atoms that fall near the power plant. Therefore, the power plant and its surroundings are contaminated by radioactive atoms that fire in every directions.

Workers on site protect themselves in a garment that covers them completely and put a mask on the face to avoid breathing radioactive dust. But they can do nothing against the bombing from radioactivity and cannot stay long there.

When you are away and there are few radioactive atoms, you are less likely to be bombed. The main problem is food and drink.

Most of the radioactive atoms can fire only once, one or two shells at a time. Then they are no longer radioactive. Some fire very quickly and the pollution does not last long due to lack of ammunition. This is the case for the atom called “iodine 131” which was rejected by the Fukushima nuclear power plant. After eight days, only the half of them are radioactive. After sixteen days, only a quarter remains. And so on … As the atom called “cesium 137”, it takes thirty years and therefore the radioactive pollution will remain a long time! The pollution should be monitored for years to protect oneselves.

The becquerel is used to count the number of radioactive atoms: if you are told there is 1000 becquerels, it means that there are 1000 shelling per second.

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