1. A VERY BRIEF HISTORY OF TIME
By: Brian Williams

2. What are “things” made of?
Aristotle- four elements
Earth, Water, Air, and Fire
Atomic Theory- All things are made up of small, indivisible pieces of matter called atoms. Proposed by John Dalton in the early 1800’s.

3. What makes “matter” move?
Pre-Newton- Science was descriptive, based on observation
Isaac Newton- Provided qualitative descriptions of motion, developed three laws of motion; the father of “Classical Mechanics”

4. What is matter REALLY made of?
Electron- Discovered in 1897 by J.J. Thomson, using cathode rays. Thomson was able to measure e/m, and thus deduce the mass of the electron.
Nucleus- Discovered in 1910 by Ernest Rutherford while doing experiments with alpha particles.
Bohr Model- negatively charged electrons orbit a small, positively charged nucleus, the atom consists of mostly empty space.

5. What’s the problem?
The Bohr Model wasn’t consistent with classical mechanics.
In fact, there was no way for classical mechanics to explain the atom, so a new theory was required!