Who was the First to Prove that Atoms Exist?

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Philosophers in ancient Greece first thought of atoms, but could not prove that all things were actually made up of atoms. John Dalton, a British scientist in 1803, proved that it is true, although the atoms were too small to be seen through the microscopes made at that time. Dalton knew that all substances are made up of elements like, water is made of hydrogen and oxygen. Also, any amount of a pure substance always contains the same elements in the same proportions. He also showed that atoms of different elements have different weight.

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