The Origins of Modern Atomic Theory

In 1827 botanist Robert Brown used a microscope to look at dust grains floating in water and observed that they seemed to move about erratically randomly just jiggling from side to side. This phenomenon became known as Brownian motion and it seemed to support the idea that there was some kind of force being exerted upon these grains of dust by atoms. In 1905 Albert Einstein explained Brownian motion in terms of the water molecules continuously knocking the grains of dust about so that when more water molecules hit one side of the grain of dust it moved. For example we know now that two hydrogen atoms and one oxygen atom make up a molecule of water. Dalton is considered to be the originator of modern