1. The Structure of the Atom

2. History of Atomic Theory

3. History of Atomic Theory
Greeks from the 5th century came up with the idea of atoms (Hewitt 209)
Aristotle rejected the idea. He said that there were only 4 elements (earth, air, water, and fire)
Since he was so influential, Aristotle’s ideas lasted for a very long time

4. History of Atomic Theory
It was not until the 1800’s that John Dalton came along and revived the hypothesis about the atom
Law of Definite and Multiple Proportions

5. History of Atomic Theory
J.J. Thompson discovered the electron – Plum Pudding Model
Earnest Rutherford discovered the nucleus – Nuclear Model
Niels Bohr came up with an idea on how the electrons orbit the nucleus – The Bohr Model
Max Planck, Louis de Broglie, Heisenberg, Schrodinger all contributed to the Quantum Model of the Atom

6. Evidence of Atoms
Brownian Motion!
Watch the video!

7. How small are atoms? They are really tiny!
Compare yourself to the size of an average star.
Your size compared to the star is how small an atom is compared to you! (Hewitt 210).
Diameter of an atom is to the diameter of an apple, as the diameter of an apple is to the diameter of the Earth (Hewitt 210)

8. How numerous are atoms? 18 grams of water =
That is more than the number of drops of water in the world (Hewitt 210).
1 liter of air = about 1023 atoms

9. How fast are atoms? They are always moving!
Solids = atoms vibrate about a fixed position
Liquids = atoms move more easily past one another
Gases = atoms move rapidly
In the atmosphere, they move “at speeds up to 10 times the speed of sound” (Hewitt 211)
Your breath diffuses throughout the entire Earth
Other people are breathing in atoms of your breath! (Hewitt 211)

10. How old are atoms?
“Many atoms in your body are nearly as old as the universe itself” (Hewitt 211)
“The origin of the lightest atoms goes back to the origin of the universe, and most heavier atoms are older than the Sun and Earth” (Hewitt 211)
We are always recycling atoms!

11. Works Cited
Hewitt, Paul. “Conceptual Physics Twelfth Edition.” San Francisco: Pearson, Print.