how do we know that things are really made from atoms?

From rocks to trees, microorganisms, incest, humans, and everything around us is made up of atoms. Atom is made up of a bundle of tiny things. We can’t see it with the naked eye. Atoms are smaller than the wavelength of the visible rays of light. Therefore it can not be seen with the most powerful light focusing microscope. Atom can only be seen with an electron microscope.

Discovery of small particles: Dutch scientist Jan Ingenhousz was the first to observe atoms during his experiment in 1785. When dust particles were darting the surface of alcohol in his lab. In 1827, Scottish botanist Robert Brown observe the same particles during his experiment. He repeated the experiment on the rock dust and see the same particles that are not alive. After a century Einstein explained this by Brownian motion. In 1908, it proved that atoms were real. After the discovery of the atom, it becomes a matter of surprise that from what atom made.