Supporting 21st Century Science GCSE

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Topic: Radioactive materials

The new items published under this topic are as follows.


What exactly is Polonium-210, and why is it so deadly?

Polonium-210 was allegedly used to murder Alexander Litvinenko, o­n November 23, 2006. According to Britain's Health Protection Agency, traces of polonium were found in his urine, as well as in several locations he had visited shortly before becoming ill. 

Polonium-210  is an isotope of  the element Polonium. Polonium has an  atomic number of 84. It contains 84 protons in its nucleus. Different isotopes contain different numbers of neutrons in the nucleus. Polonium-210 contains 126  neutrons. ( 210 - 84)

Polonium is a very scarce element, and is o­nly found in extremely small quantities in the Earth's crust. It was first discovered by Marie Curie in 1898. It is mainly used in industry to neutralise static electricity in certain manufacturing processes. Polonium-210 has also been used as a heat source to power thermoelectric cells in artificial satellites.

Polonium-210 emits high energy alpha particles. These alpha particles can cause intense ionisation. Outside the body, they are unable to penetrate the skin, and are easily absorbed by a thin sheet of a paper. This is because their energy is rapidly absorbed as a result of the high interactions with atoms. o­nce inside the body the the intense energy alpha particles can cause severe damage to cells and organs. Small amounts no larger that a few grains of salt can cause severe radiation sickness. Such is the intensity of the alpha particles, that o­nly 0.5 g of Polonium would be sufficient to raise its temperature by 500 degrees centigrade.

Polonium is extremely toxic.  Weight for weight, polonium is almost 250 billion times as toxic as hydrogen cyanide.

The half-life of radioactive element is the time it takes for the substance to reach o­ne-half of its intensity. This is the time it takes for half of the radioactive nuclei to decay (change into other elements). Polonium-210 has a half-life of 138.376 days. A short-half life is useful when the intensity is required to reduce to a virtually negligible amount after it has done its damage. The longer it remains, the less obvious its presence becomes, and more difficult to detect. O­nce inside the body the Biological or effective half-life needs to be considered. The Biological or effective half-life is the time required for the amount of a radionuclide deposited in a living organism to be diminished 50 percent as a  result of the combined action of radioactive decay and biological elimination.

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Radiation Therapy

Radiation therapy is used in the treatment of cancer. This involves the use of penetrating beams of high energy waves or streams of particles called radiation.

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Understanding Radiation

Here is a useful o­nline resource which provides an introduction to radiation and the applications of radioactivity. Heath and Safety issues are also covered.

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Case Study: Radon Levels and Health

Radon is a radioactive gas that occurs naturally. Special precautions are needed to prevent radon gas from entering homes from ground sources.

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Legacy of a Nuclear Disaster

On April 26th 1986, a combination of human error and poor system technology resulted in o­ne of the greatest nuclear power disasters the world has experienced. 

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Radioactive Decay Demonstrations

Looking for some interactive demonstrations for radioactive decay?

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