14 / 12 / 2010

HALF-4: meaning and examples

Hello again.

Today we continue with our series of Daily Vitamins about expressions and compound words with half.

Today's expression is: half-life 

Meaning: the period of time it takes for a substance undergoing decay to decrease by half. The name was originally used to describe the time taken for the radioactivity of a substance to fall to half of its original level.

Example 1:
Some scientists say that plastic has a half-life of between 450 and 1000 years; so use plastic as little as possible.

Example 2:
Some nuclear substances have a half-life of millions of years.

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Enjoy the rest of your day.

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