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(SCIENCE TREK MUSIC)

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JOAN CARTAN-HANSEN, HOST: How do 
scientists tell if a substance

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is an acid or a base?

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They check its pH value.

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PH is a scale scientists use to 
determine if a chemical is an

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acid or a base.

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It goes from zero to 14.

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Acids are categorized from zero 
being the strongest to 6 which

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is the weakest.

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7 is neutral, neither an acid 
nor a base.

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Water is generally 
pretty neutral.

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Bases have a pH value 
of 8 to 14.

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The higher the number, the 
stronger the base.

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Bases are used to 
neutralize acids.

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Drain cleaners are made from 
sodium hydroxide, a strong base.

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Cooking ingredients like baking 
soda and cream of tartar are

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weaker bases.

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Your pancreas makes a fluid rich 
in the base Bicarbonate to

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neutralize stomach acid before 
the acid moves into your

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amall intestines.

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People will also take 
bicarbonate to reduce heartburn.

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Famers use lime, a base, to help 
neutralize acidic soil to help

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plants grow.

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To learn more about chemistry, 
check out the Science Trek

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website.

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You'll find it at 
ScienceTrek.org.