-
340
340 BCE - Aristotle's 5 Elements
Aristotle believed that there were only five elements: air, earth, water, fire, and Aether. Aristotle believed that all matter was made up either of one of the elements. He believed the stars and planets were made of Aether. -
340
Aristotle's Model
-
John Dalton's Theory
Dalton created a scientific theory based off of Democritus's atom idea, Atoms are the same in same elements though. His theory also introduced compounds, which are made when different elements combine. The final part of his theory was when atoms of different elements are joined, separated, or rearranged, a chemical reactions will happen -
Dalton's model
-
J. J. Thompson
J. J. Thompson, a physicist who invented the Cathode Ray. When high energy was moved from the negative cathode plate through a vacuum sealed container to a positive plate, it created a beam of electrons. This resulted in the Plum Pudding model. Thompson thought all of the particles he saw were clumped together (much like plum pudding). So solids could made when harder substances were packed together. -
Thomson's model
-
Earnest Rutherford
During his gold foil alpha particle scattering experiment, He observed a change in what should have been seen. The beam deflected in multiple directions leading him to determine that atoms had a center or nucleus. This led to the making of the Rutherford atomic model a year later in 1911. -
Earnest's model
-
492 BCE - Democritus' Discovery
Democritus stated that all objects are made up of little indestructible and indivisible things called atoms. However, his discovery was often questioned because he could not explain the chemical side of his 'atom' idea. -
Democritus's model
