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What is it?
An indicator is a substance that indicates (or shows) something about a solution by changing color. Indicators are useful because they reveal the presence of various different chemical compounds in a solution ... or tell you whether a solution is acid or base.
Litmus paper is an indicator that is often used to determine the pH of a solution. If a drop of the solution turns the litmus paper red, the solution is an acid: If the litmus paper turns blue, it's a base.
Give me an example! Indicators can take many forms. Have you ever sniffed a carton of milk to see whether it's sour? Your nose is acting as an indicator and telling that the milk is either okay to drink or it's time time pour it down the sink! |
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