1. Science 9 Greeks to geeks

2. A Short History of Investigating Matter

3. Around 450 BC, Empedocles suggested that all matter was made of 4 elements:
Earth, Air, Water and Fire

4. I think this pretty well covers everything!
Empedocles

5. I could break you right down into atoms! (But nothing smaller!)
LOOK OUT SONNY!
I could break you right down into atoms! (But nothing smaller!)
Also around 400 BC , Democritus proposed that all matter could be broken down into atoms. These atoms could not be broken down farther.

6. Sorry Democritus!
I am the famous Aristotle and I don’t like your “atom” idea. I disagree and people are going to believe me for 2000 years. So take THAT!

7. Notes
Empedocles– suggests Earth, Air, Water Fire, called the four element theory
Democritus suggests that matter is made of atoms.(invisible particles too small to see)
Aristotle – teaches the four element theory and it sticks!

8. Guys, if we could just change this lead and copper into GOLD, we’ll be filthy rich! We can drive around in brand new SUV’s with great rims and XM radio!
Some Alchemists

9. In the Middle Ages scholars searched for the “Philosopher’s Stone” which would help them change Lead or Copper into GOLD!

10. Much later, Harry Potter became involved in the same search?????
Gold does not tarnish so it lives for ever and the philosopher’s stone would allow them to live forever

11. In 1669, Hennig Brandt distilled some urine
In 1669, Hennig Brandt distilled some urine. He found a pasty white solid which glowed in the dark!
He had actually discovered a new element “phosphorus”. He didn’t think about it being a new element because he still believed there were only the four.
Hey! This came from pee !!!

12. Notes
Alchemists: look for the philosophers stone to turn cheap metals into gold. This would be possible in the four element theory. They accidentally begin to discover elements.

13. NO! I am NOT cutting my hair!!
I also disagree with Aristotle! I think there are WAY more than four elements!
Sir Robert Boyle
Robert Boyle ( ), an English scientist thought air was a mixture rather than an element. He also thought Brandt’s white paste and gold were elements.

14. HEY! Maybe I can get on the OPRAH show to help sell my book!
In 1661, Boyle published a book called “The Sceptical Chymist”
HEY! Maybe I can get on the OPRAH show to help sell my book!

15. Wait a minute! I wrote that song!!!
In the late 1700’s the Scientific Revolution was taking place. Many old ideas were being challenged!
“You say you want a revolution, we-ell you know-oh oh, we all wanna change the world….”
Wait a minute! I wrote that song!!!
Henry Cavendish

16. In 1766, Henry Cavendish mixed a metal with acid making flammable gas which was lighter than air. We now know the gas was _________________
(another element is discovered)
hydrogen

17. In 1774, Joseph Priestley decomposed mercuric oxide into liquid mercury and a gas. He called the gas “lively air” because it made mice move around faster!

18. Joseph Priestley (1733 – 1804)

19. Antoine Lavoisier experimented with Priestley’s gas
Antoine Lavoisier experimented with Priestley’s gas. He concluded that air must be a mixture of at least 2 gases, one that supports burning and one that does not.
Antoine Lavoisier
(1743 – 1794)

20. Hey! Have you heard about Priestley’s new gas?
Yeah, sounds cool!
Hey! Have you heard about Priestley’s new gas?

21. Cavendish took some of his “own” gas (hydrogen) and using Priestley’s method produced some oxygen. He then burned the hydrogen in oxygen and got none other than water! Of course, he wrote a report on this!

22. I’ve read Cavendish’s report and I think I’ve got it, by George!
When matter is broken down, the final form is an element. You can’t break it down any more!
Antoine Lavoisier

23. Lavoisier’s wife, Marie also helped in his research but her contribution is seldom mentioned!

24. I’m going to publish all this stuff, but I don’t think I’ll mention Priestley or Cavendish, or even Marie, for that matter. I’ll also take credit for naming the two gases, hydrogen and oxygen!

25. During the French Revolution, Lavoisier was unfortunately executed by the guillotine!
Can someone help me?
That was too bad. He contributed a lot to our knowledge of science and chemistry!

26. In the early 1800’s, John Dalton came up with the ATOMIC THEORY.

27. NOTES
Dalton’s Atomic Theory
All matter is made of atoms.
Atoms are indivisible and indestructible.
All atoms of a given element are identical in mass and properties
Compounds are formed by a combination of two or more different kinds of atoms.

28. Compounds are composed of little “balls” called atoms, joined together by “bonds” to form molecules.

29. crookes tube
J.J. Thomson's Experiments
Using Crooke’s tubes and other equipment, J.J. Thomson discovered the electron and measured its e/m (charge to mass) ratio.
Later, “e” was found and the mass of an electron was found to be × grams (much lighter than H)

30. Thomson’s Plum Pudding Model

31. Ernest Rutherford

32. Rutherford’s Scattering Experiment

33. Rutherford could not explain why the electron didn’t fall into the nucleus and destroy the atom.?

34. I think I can help!
Neils Bohr

35. This model is really cool !!
According to Bohr, each energy “level” corresponded to a different “orbit” of an electron around the atom. (Like planets around the sun.)
This model is really cool !!

36. Notes
J. J. Thompson – discovered the electron. Proposed the raisin bun or plum pudding model with the electron (raisins) stuck in the bun.
Rutherford – discovered the nucleus.
Could not figure out why electrons did not crash into the nucleus.

37. Notes
Niels Bohr – discovered that electrons moved around the nucleus. Is credited with the first working model of an atom.
Mendeleev: Made the first periodic table. Predicted element that were previously unknown.

38. History of the atom