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450 BCE
the four elements
A greek scholar named Empedocles discovered that matter was made up of four elements: Earth, Air, Fire, and Water. what lead him to his discovery was that he experimented with some of his theories. One of his theories he experimented with was air may be invisible but it takes up space and that had him thinking. -
Period: 450 BCE to
colton's matter timeline
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400 BCE
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Later on, another greek Democritus suggested that matter was made up of a whole bunch of tiny particles that could not be broken down further. Democritus's ideas were never really accepted because an influential figure at the time did not believe them so he convinced people to think the same way he does. -
350 BCE
Aristotle believed in the four elements
Even later on in 350 B.C, Aristotle believed in Empedocles's four-element. Aristotle was a big figure at the time and since he believed Empedocles four-element so did many others for almost 2000 years. -
1 CE
A.D 500-1600
They invented chemical symbols for substances that we now call elements and compounds. Also, they invented tools you can use in the laboratory that we still use in today's date like beakers, stirring rods, etc. the people still believe in the four elements. -
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An English scientist Robert Boyle invented a new definition for the word element because he did not believe in the four elements. The new word he invented was simple unmitigated bodies. This became the modern definition of an element. He did not believe air was an element as well but rather a mixture. -
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Joseph Priestley was the first person to isolate oxygen. Later on, Antonie Lavoisier experimenting with Joseph Priestley's oxygen realized that air must be a mixture of at least two gasses. -
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Dalton's atomic model couldn't add up the reasoning why on a dry winter day you could get a small shock when touching a metal doorknob. in 1831, Michael Faraday found that electric current could cause chemic changes in some compounds in solutions. -
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at this time it was accepted that matter was made of elements. John Dalton's atomic model for matter stated that "all matter is made of atoms too small to see". Also, he said atoms cannot be created, destroyed, or subdivided in chemical changes. -
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Japanese scientist H. Nagaoka, working at the same time modeled an atom as a large positive sphere surrounded by a ring of negative electrons. J.J Thomas revered the atomic model further. the new model became the raisin bun model. -
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Ernest Rutherford working at McGill University in Montreal designed an experiment to test Thomson and Nagakokas models. he predicted based on the Thomson raisin buns model that the particles would pass straight through the gold foil. the particles bounced straight back from the gold foil.
