Albert Einstein was the first one to prove that matter is composed of very tiny particles called atoms and he calculated its size. He was able to prove this by spreading pollengrains on the surface of water. When you look at these pollen grains with your naked eyes you will see them completely stable and not moving at all. If you looked threw a microscope you will see what Albert Einstein saw. He saw these pollengrains vibrating in a continuous manner which means that there are tiny unseen particles that are pushing these pollengrains. From these vibrations Einstein was able to calculate the size of these atoms. To Imagine its size, the thickness of a avery thin hair from your head has approximately one million of these atoms. This was Albert Einstein's first published paper.