3.  624-574 BC Thales of Miletus Says that water is simple because it could not be broken down into smaller pieces. 500-428 BC  500-428 BC Anaxgoras and Empedocles Changes in matter happen because of changes in indivisible particles

4.  484-428 BC Empedocles Matter was Separated into four elements; earth, water, fire and air.  460-370 BC Democritus Democritus named particles atoms.

5.  1704 Isaac Newton The universe is a mechanical universe with small solid that are always moving  1873 James Clerk Maxwell Magnets and electricity filled empty space in atoms

6.  1897 J.J. Thomson Found canal rays were part of a proton, H + 1898 Marie Skodowska Curie Named the decomposing process of uranium and thorium to be radioactivity. Pierre Curie While Curie was working on radioactive substances, Curie discovered gamma rays.

7.  1903  Nagaoka  Saturnian model of the atom where there is flat rings of electrons moving around a positively charged particle.  1905  Albert Einstein  Publishes theory on special relativity and states that matter can be changed into energy.

8.  1923 Louis Victor de Broglie Electrons are similar to both particles and waves.  1930 Erwin Schrodinger  Saw electrons as a continuous cloud and made wave mechanics to be a mathematical model for the atom. 1932  James Chadwick Discovered neutral atomic particle with similar mass to a proton, the neutron was made by using alpha particles.

10.  http://ffden2.phys.uaf.edu212_spring200 5.web.dirashley_anderson/atomic_timeli ne.html 