#5 A Brief History of Time - Elementary particles and the forces of nature

Chapter 5:

1. Aristotle VS. Democritus

   1. Aristotle believes all the matter in the universe was made up of 4 elements- earth, air, fire, and water

   2. Democritus holds that matter was made of various different kinds of atoms (atom means indivisible in Greek)

2. Brownian motion

   1. In 1905, Einstein pointed out that Brownian motion can be explained by the irregular random motion of small particles of dust suspended in the liquid.

3. Quarks

   1. Protons and electrons are made of quarks

   2. There can be an entire world made of antiparticles ( mostly antiquarks)

4. Force carrying particles

   1. Gravitational force

   2. Electromagnetic force

   3. Weak nuclear force

   4. Strong nuclear force

5. Combined symmetry CPT