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Democritus
Democritus discovered the invisible atom and believed that the atom is indestructible. Democritus is a Greek philosopher who proposed the idea that matter is made of atoms or atomos. When Democritus tried to test his ideas his experiments were rejected because he did not have the equipment.
YouTube Link:https: //www.youtube.com/watch?v=TgWn91ap99A -
John Dalton
John Dalton was an English chemist whose ideas formed the atomic theory of matter.Dalton discovered that all elements and their atoms are identical. All elements are made up of there own atoms.Tin is made up of tin atoms. He also known on how all matter is made of atoms and a compound is two or more atoms combined into one.He had idea that it is impossible to destroy an atom.He also found that there was a ratio of elements in a compound.
You Tube Link: https://www.youtube.com/watch?v=sDoH5fPTOfo -
J.J. Thompson
J.J. Thompson was an English scientist who discovered the electron. He discovered it when he was working with gas discharge tubes. When he noticed the movements in the tubes he called them cathode rays. The rays moved from the negative end to the positive end. Then he noticed that the rays where negatively charged particles which are electrons.
You tube Link: https://www.youtube.com/watch?v=JwdGFZA3WOs -
Niels Bohr
Niels Bohr was a Danish physicist.He proposed the model of the atom that is similar to the model of the solar system.The electrons go around the nucleus like the planets go around the sun.Bohr discovered the structure of an atom and the energy levels of an atom.An energy level is the distance from the nucleus.Each level can hold a certain number of electrons.When the atom loses electrons it energy lowers. It is the opposite if it gains.
You Tube Link: https://www.youtube.com/watch?v=Cn6v5ygyZHQ -
Lord Ernest Rutherford
Rutherford conducted an experiment.It was called the gold foil experiment.He used the following items: gold foil, alpha particle shooter, and alpha particles.What he did is that he took the alpha particles and shot them at the gold foil.The result was that some of the particles passed straight through the gold foil, others were deflected.The experiment showed atoms have a small positively charged nucleus and it repels alpha particles.
You Tube Link: https://www.youtube.com/watch?v=5pZj0u_XMbc
