1. What are the basic building blocks of matter? Empedocles – Earth, Air, Water, Fire Democritus – “Nothing exists except atoms and space; everything else is opinion” “Everything existing in the universe is the fruit of chance and necessity.” Atoms

2. Leave it to the Chemists Antoine Lavoisier: Changed fanciful names to meaningful names, eg.: Flowers of Zinc  Zinc Oxide Different Gasses in air Phases of matter Water = Hydrogen + Oxygen (1:8)

3. Dalton and Mendeleev John Dalton: Atoms of different sizes are multiples of Hydrogen Mendeleev: Group “elements” by their chemical properties and weights Periodic Table (1870) had gaps Periodic Table (1870) had gaps

4. Michael Faraday and Charge to mass ratios (q/m) Separated Hydrogen and Chlorine Ions (Electrolysis) Particles of electricity in cathode rays Other Faraday things... electric motors electric motors electromagnetic induction electromagnetic induction fields fields

5. What keeps the elements together? GravityElectricityMagnetismOptics Unification: Electricity + Magnetism + Optics = Electromagnetism

6. More on Unification Electricity can produce magnetism Magnetism can (sort of) produce electricity Electricity produces magnetism in more than one way Waves of Electricity and Magnetism. Speed of these waves = 3 × 10^8 m/s!!

7. How do these “Forces” Work? Newton: Action at a distance Inverse Square Law Inverse Square Law Faraday: Fields

8. Back to the Particles... What does the atom look like? J.J. Thomson: Plum Pudding model Ernest Rutherford: Nuclear Atom Scattering experiments with alphas on Gold

9. An aside on Radioactivity Three types of Radioactivity: Alphas: Positively charged; Helium nuclei; can be stopped by paper Betas: Negatively charged; electrons; stopped by light metals Gammas: Uncharged; electromagnetic radiation; stopped by thick sheets of lead

10. Back to the nuclear atom.. Positively charged center with electrons (Particles of electricity) revolving around What, if anything, is between electrons and nucleus? Empty space: Democritus’ vacuum