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400
Democritus
In 400 B.C. a man named Democritus came up with the idea that everything is made up of little circles he called atomos. He thought that if you kept cutting something into smaller and smaller pieces it would eventualy just be an atamos. Also he said that all materials are made from different kinds of atamos and that they were industructable. -
John Dalton
It wasn't until a long time later that John Dalton experimented with atoms. He found that different types of atoms have different wieghts which he tried to find some of them. He also found that atoms can be put together with different kinds to form a chemical reaction. -
J. J. Thomson
Later on J. J. Thomson found that atoms were not just one circle. He found that they were made of smaller circles making up the atom. One of these circles he found as the electron. These electrons were found to have a negative charge and they would be embeded inside a positive charge. He called them plums in plum pudding. -
Ernest Rutherford
Ernest Rutherford had worked with J. J. Thomson in his experiments. But then Rutherford looked further into the atoms. He found that the atoms were made up of the known electrons and he then discovered protons and nuetrons which made up the nucleus with the electrons around it. -
Niels Bohr
Soon later Niels Bohr made more discoveries about the atom. He found ways that the parts of the atoms relate. He also found that electrons orbit around the nucleus. -
Modern
In the modern atom we know that atoms are made from protons and neutrons that make up a nucleus with electrons orbiting that nucleus. Atoms can be used to make molecules and can be mixed to make any substance.
