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450 BCE
Empedocles
A Greek scholar named Empedocles proposed matter was mad out of 4 elements, fire, earth, water, wind. These elements mixed together could make other substances -
400 BCE
Democritus
A Greek Democritus suggested matter was made out of small particles. He called them partical atoms after the Greek work atmos which means invisible -
350 BCE
Aristotle
This philosopher believed in Empedocles theory despite the more recent atomic theory -
Invention of science tools
This time period was very important for science and experiments. During this time many laboratories were made and tools we still use this everyday such as beakers, filters, stirring rods and distillation apparatus. -
Robert Boyle
An english scientist, Robert Boyle did not belive in the four-element model. He went on to make his own diffenition for a element " a pure substance that cannot be chemically broken down into simpler substacnes. He also belived that air was not a element. -
Jsoeph Priestley
Jsoeph Priestley was the first person to isolate oxygen scientifically, But he did not know that oxygen was a element. In concludion Lavoisier stated that air must be a mixture of at least two gases, one of which is oxygen. -
Dalton's atomic model
Dalton's atomic model did not explain why, on a dry winter day, you get a spark when you touch a metal doornob. In 1831, Michael Faraday found that electric currents could cause chemic changes in some compounds in solution Daltons modified verison was:
- Matter must contain positive and negative charges.
- Opposite charges attract and like charges repel.
- Atoms combine to form molecules because of electrical attractions between atoms. -
J.J Thomson
Later on J.J Thomson revised the atomic model even further, to explain his discovery of very light negative particles, called electrons. His new model became known as the raisinbun model.
