Ask Me Everything9

hy is uranium

dangerous?

Uranium is radioactive. And there’s the problem — because radioactivity is dangerous, uranium is dangerous. Radioactive substances can cause sickness, burns, cancer, and even death. But even though it’s dangerous, radioactivity can be useful, too. For example, without it, you might not be able to turn on your lights.

Cockroaches can

survive up to 16 times morę radiation than humans can. Fruit flies

are even tougher— they are able to survive up to

Where do radioactive substances come from?

Primordial—these W A are radioisotopes that have existed sińce before Earth was formed.

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/lO Cosmogenic—these w u are created when a cosmic ray (a particie from space) hits the nucleus of an atom and changes it.

flO Produced by W w humans—many of the radioisotopes used in industry and medicine are madę in nuclear reactors. Some of the radioactive particles found in naturę today were produced by nuclear weapons tests in the past.

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Half-lives

Some radioisotopes decay faster than others. The time that it takes for half of the atoms in a piece of a radioactive element to decay is called the elemenfs half-life. Half-lives can rangę from a fraction of a second to billions of years.

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When radioactivity was discovered, some people thought that it was good for them. They drank glowing radioactive drinks, not knowing how seriously dangerous they were.

radioisotope

polonium-214

radium-221

strontium-90

carbon-14

uranium-238

half-life

160 microseconds 30 seconds 9 minutes 5,730 years 4,500 million years

(c) 2011 Dorlinl Kindersley. Ali Rights Reserved.