Democritus, an ancient Greek philosopher, was not the first to propose an atomic theory, as his mentor Leucippus originally proposed it. Democritus adopted the theory, developed it further, and provided a more detailed a... More »

Because ancient Greek thinkers such as Democritus lacked sophisticated technology and tools such as the microscope, his theory of the atom was due more to thought experimentation than to hard empirical observation, as us... More »

Democritus's particle theory states that each organism in the universe is made up of particles so minuscule that nothing smaller is possible. Democritus regarded those particles, commonly known as atoms, as unchangeable ... More »

Because ancient Greek thinkers such as Democritus lacked sophisticated technology and tools such as the microscope, his theory of the atom was due more to thought experimentation than to hard empirical observation, as us... More »

Robert Millikan contributed to atomic theory by measuring the charge on an electron. He accomplished this by pulling the electrical charge out of a water or oil molecule and measuring it. More »

www.reference.com Science Chemistry Atoms & Molecules

Democritus' model of the atom was simply a round, solid ball. Democritus knew nothing of separate protons, neutrons and electrons; all he knew was that everything physical was composed of atoms, according to Boise State ... More »

In 1905, Albert Einstein published an analysis in which he devised a mathematical way to predict the size of both atoms and molecules. At the time, the science of atoms was still in its infancy, but Einstein's test was c... More »