Carbon dating physics gcse

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To do this, a small amount is injected into the pipe. It is then detected with a GM counter above ground. If a gamma source is placed on one side of the welded metal, and a photographic film on the other side, weak points or air bubbles will show up on the film, like an X-ray. Because Gamma rays can kill living cells, they are used to kill cancer cells without having to resort to difficult surgery. This is called " Radiotherapy ", and works because cancer cells can't repair themselves when damaged by gamma rays, as healthy cells can. It's vital to get the dose correct - too much and you'll damage too many healthy cells, too little and you won't stop the cancer from spreading in time.

uses of nuclear radiation

Some cancers are easier to treat with radiotherapy than others - it's not too difficult to aim gamma rays at a breast tumour, but for lung cancer it's much harder to avoid damaging healthy cells. Also, lungs are more easily damaged by gamma rays, therefore other treatments may be used. Let's see how much you've learned: Much of the material on this page is the result of a Year 10 group work lesson, mainly using the "Physics for You" textbook. Each group presented their material to the class. Smoke alarms contain a weak source made of Americium Alpha particles are emitted from here, which ionise the air, so that the air conducts electricity and a small current flows.

If smoke enters the alarm, this absorbs the a particles, the current reduces, and the alarm sounds. Am has a half-life of years.

Carbon Dating-P4

The radiation kills microbes, prolongs the food's shelf-life. Irradiated food does not itself become radioactive; however in some cases there may be subtle chemical changes and this may affect the taste. In the UK only correctly labelled irradiated herbs, spices or vegetable seasonings are allowed. Major supermarkets say they will not stock irradiated foods because people are reluctant to buy them, even though the food itself is not radioactive. Beta radiation is used in industry in detectors that monitor and control the thickness of materials such as paper, plastic and aluminium.

BBC Bitesize - GCSE Physics (Single Science) - Uses and hazards of radiation - Revision 1

The thicker the material, the more radiation is absorbed and the less radiation reaches the detector. The detector then sends signals to the equipment that adjusts the thickness of the material.

Radioactivity, Half-Life & Inverse Square Law - GCSE & A-level Physics

Alpha radiation is not used because it gets absorbed too quickly even by paper, whereas gamma radiation hardly gets absorbed at all. A source with a fairly long half-life a few years is chosen so that it does not need to be replaced often. One type of smoke detector also called smoke alarm operates using ionisation.

The Americium emits alpha particles that ionise the air between the two charged metal plates, resulting in a small current flowing. If smoke particles enter the alarm, they 1 gather up and neutralise the ions and 2 absorb some of the alpha particles, so both the ionisation rate and the number of ions gets less, the current reduces, a microchip notices this and triggers the alarm.

The half-life of Am is years, so has many years of useful service to offer! Carbon is a radioactive isotope of carbon it has two extra neutrons in its nucleus making it unstable. The amount of carbon in the atmosphere has not changed in thousands of years. Even though it decays into nitrogen, new carbon is always being formed when cosmic rays hit atoms high in the atmosphere.

1stclass-ltd.com/wp-content/accessing/3600-wie-kann.php Plants absorb carbon dioxide from the atmosphere and animals eat plants. This means all living things have radioactive carbon in them. When an organism, eg a tree, dies it stops taking in carbon dioxide. The amount of carbon in the wood decreases with time as it decays with a half-life of about years into nitrogen.


By comparing how much carbon there is in the dead organism with the amount in a living one, the age of the dead organism can be estimated. Rocks can be dated in a similar way, by measuring the proportion of radioactive uranium in some cases, or potassium in others. These isotopes have much longer half-lives than carbon, so are suitable for investigating ancient rocks. The half-life of uranium is million years.

When it decays, it forms thorium which is also unstable. After a series of radioactive isotopes are formed it eventually becomes lead, which is stable.

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The age of the rock can be calculated if the ratio of uranium to lead is known. As the rock gets older the proportion of lead increases.

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If half of the uranium has turned into lead the rock will be million years old. Graph shows the amount of carbon decreasing over time.

It halves every years. The amount halves every years. Here are some examples of how nuclear radiation is used: In industry they can be used to: When a radioactive chemical is used in this way it is not normally harmful, because: