Models of Matter

atoms

200

A greek democritus suggested that matter is made up of tiny particles that can not be broken down further

about 350 B.C.

350

The Philosopher Aristotle believed in Empedocles "four elements" model despite the more recent "atomic" model

about 450 B.C.

450

a greek scholar named Empedocles proposed that matter was composed of four elements Water,Fire.Air and Earth. these elements mixed togather in different proportions to yield diffrent substances.

A.D. 500-1600

500

Many alchemists believed that they did. ( combination of philosopher, mystic, magician and chemist.

1650

Mar 14, 1650

An english scientist , Robert Boyle, did not belive in the four elements model. He made a new definition for the word element.

late 1700s

Mar 14, 1700

Joseph Priestly was the first person to isolate oxygen scientifically, but he didnt know that oxygen is a element. that fact was recognized ny Antoine Lavoisier.

1800s

Mar 14, 1800

Daltons atomic model cannot explain why, on a dry winter day, you get a spark when you touch a metal doorknob. ( chargeg an ekectricity that may build up an object )

1808

Mar 14, 1808

by this time it was generally accepted that matter was made of elements : the two models have come togather

1904

Mar 14, 1904

J.J. thomson revised that atomic model further: to explane his discovery to very light negative particles , called electrons.

1911

Mar 14, 1911

Ernest Rutherford working at McGill university in montreal, designed an experiment to test Thomson's and Nagaoka's model.