This drawing represents a comet bringing atmospheric molecules and possibly primitive life forms to the Earth's surface.
Click on image for full size
JPL/NASA
Base
Like an
acid, a
base is a substance capable of dissolving things.
There are many bases. Here are a few: Ammonia (used as a cleaner), Calcium hydroxide (used in mortar for construction), Magnesium hydroxide (otherwise known as milk of magnesia; used as a laxative or antacid), Sodium hydroxide (used as an oven cleaner).
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Nitric acid is a very strong kind of acid. If you got some on your skin, it would burn you! Nitric acid has nitrogen, oxygen, and hydrogen atoms in it. Earth's atmosphere has a very, very tiny bit of nitric
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Sulfuric acid is a very common type of acid. Acid rain has sulfuric acid in it. Acid rain harms plants, fish, and other living things. A type of air pollution causes acid rain. When people burn fossil
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Methane is a kind of gas. There is a small amount of methane in the air you breathe. A methane molecule has carbon and hydrogen atoms in it. Methane is a greenhouse gas. That means it helps make Earth
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Ammonia is a kind of gas. Ammonia molecules (NH3) have hydrogen and nitrogen atoms in them. The air you breathe has a tiny bit of ammonia in it. When plants and animals die and decay, they give off ammonia.
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There is more nitrogen gas in the air than any other kind of gas. About four out of five of the molecules in Earth's atmosphere is nitrogen gas! A molecule of nitrogen gas is made up of two nitrogen atoms.
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Oxygen (O2) is a kind of gas. A lot of the air you breathe is oxygen. That's a good thing, since we need oxygen to stay alive! About 4/5ths of the air in Earth's atmosphere is nitrogen (N2). Almost all
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Hydrogen peroxide (H2O2) is a kind of chemical. A molecule of hydrogen peroxide has oxygen and hydrogen atoms in it. Hydrogen peroxide is a clear liquid. Hydrogen peroxide is in some liquids that are used
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