dangers and uses of radiation

radiation in the environment

A low level of radiation occurs naturally in the environment. This is called background radiation. One source of background radiation is rocks, which may contain small amounts of radioactive elements such as uranium. Another source is cosmic rays. These are charged particles that arrive on Earth from outer space. Background radiation is generally considered to be safe for living things.

dangers of radiation

Long-term or high-dose exposure to radiation can harm both living and nonliving things. Radiation knocks electrons out of atoms and changes them to ions. It also breaks bonds in DNA and other compounds in living things. One source of radiation that is especially dangerous to people is radon. Radon is a radioactive gas that forms in rocks underground. It can seep into basements and get trapped inside buildings. Then it may build up and become harmful to people who breathe it. Long-term exposure to radon can cause lung cancer. Exposure to higher levels of radiation can be very dangerous, even if the exposure is short-term. A single large dose of radiation can burn the skin and cause radiation sickness. Symptoms of this illness include extreme fatigue, destruction of blood cells, and loss of hair. Nonliving things can also be damaged by radiation. For example, high levels of radiation can weaken metals by removing electrons. This is a problem in nuclear power plants and space vehicles because they are exposed to very high levels of radiation. Q: Can you tell when you are being exposed to radiation? For example, can you sense radon in the air? A: Radiation cant be detected with the senses. This adds to its danger. However, there are other ways to detect it.

detecting radiation

You generally cant see, smell, taste, hear, or feel radiation. Fortunately, there are devices such as Geiger counters that can detect radiation. A Geiger counter, like the one pictured in the Figure 1.1, contains atoms of a gas that is ionized if it encounters radiation. When this happens, the gas atoms change to ions that can carry an electric current. The current causes the Geiger counter to click. The faster the clicks occur, the higher the level of radiation.

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using radiation

Despite its dangers, radioactivity has several uses. For example, it can be used to determine the ages of ancient rocks and fossils. It can also be used as a source of power to generate electricity. Radioactivity can even be used to diagnose and treat diseases, including cancer. Cancer cells grow rapidly and take up a lot of glucose for energy. Glucose containing radioactive elements can be given to patients. Cancer cells take up more of the glucose than normal cells do and give off radiation. The radiation can be detected with special machines like the one in the Figure 1.2. The radiation may also kill cancer cells.

instructional diagrams

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questions

there is a low level of natural radiation in the environment.

-->  a. true

b. false

sources of background radiation include

-->  a) cosmic rays from space.

b) atomic bomb testing.

c) nuclear power plants.

d) all of the above

background radiation is generally considered harmful to living things.

a. true

-->  b. false

radiation can cause damage by

a) knocking electrons out of atoms.

b) changing atoms to ions.

c) breaking bonds in dna.

-->  d) all of the above

only living things can be harmed by radiation.

a. true

-->  b. false

diagram questions

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