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“Atom.” The word comes from the Greek a-tomos. That means “indivisible.” When these particles were named, scientists thought atoms were the smallest bits of stuff found in nature. We now know differently, but the name stuck.
There are about 100 different kinds of atoms. Most are found in nature. Scientists make others in laboratories.
Some things are made up of only one kind of atom. They’re called “pure.” Some examples are gold, lead, and iron. Other things are made up of a combination of atoms. These include plants, wood, and plastic. How atoms are put together and held together determines whether they form an apple, a glass of water, or air in a balloon.
Atoms are always moving. Even the atoms that make up solid things like a block of wood! Of course, you can’t see or feel the movement. That’s because the atoms are so small and closely packed together.
When you think of atoms, think very small. Many millions of atoms would fit on the head of a pin.
