1. History of the Atom Activity

2. Informal assessment – monitoring group interactions and questions
Objectives:
Today I will be able to:
Explore the nature of science by completing an activity
Research a scientist to understand the history of the atom
Informal assessment – monitoring group interactions and questions
Formal assessment – analyzing student responses to the exit ticket
Common Core Connection
Build Strong Content Knowledge
Value Evidence
Come to understand other perspectives and cultures

3. Lesson Sequence Evaluate: Warm – Up
Explore: History of the Atom Research
Enage: Construction of Timeline
Elaborate: Gallery Walk
Evaluate: Exit Ticket

4. Warm - Up Complete the half sheet on atomic changes
Use the word bank on the worksheet to complete the questions

5. Objective Today I will be able to:
Explore the nature of science by researching the history of the atom
Research a scientist to understand the history of the atom

6. Homework
Study for the Atomic Structure Quiz on Friday October 10th (This Friday!)

7. Agenda Warm – Up History of the Atom Research Make a Flip Book
Exit Ticket

8. History of the Atom Research
Each member of the group will use textbooks and the computers to research their two assigned scientists

9. Analogies

10. Make an analogy
Work with your group to create a real-life analogy for the Dalton, Thomson, Bohr and Schrodinger Models of the atom
Look at Mr. Klotz’s example for guidance
Share analogies with the class

11. History of the Atom Analogy
Dalton’s Model Thomson’s Model

12. History of the Atom Analogy
Bohr Model
Sugar cookie with chocolate chips in rings around the outside
Schrodinger Model
Sugar cookie dipped in melted chocolate

13. The image of your analogy must be included in the flip book
Make a flip book
The image of your analogy must be included in the flip book

14. Flipbook Requirements
For Dalton, Thompson, Rutherford, Bohr, Schrodinger
Describe their model of the atom
Draw a picture of their model of the atom
Write and draw a picture of your analogy
For Thompson and Rutherford – Describe the experiment
For Dalton – Write the pieces of the atomic theory

15. History of the Atom Notes

16. Democritus (400 BC) Greek Philosopher
All matter is composed of tiny, indivisible parts called “atomos”
He said you cannot cut a piece of matter infinitely, but at some point you would get the smallest piece of matter possible.
Said “atomos” could not be divided any further

17. John Dalton (1803) School Teacher
Studied the ratios in which elements combine in a chemical reaction
Dalton’s Atomic Theory
All matter is composed of tiny indivisible parts called atoms (they can be broken down further, although properties will not be retained)
Atoms of the same element are exactly alike, atoms of different elements are different (not all atoms of the same element have the same mass – isotopes)
Atoms can combine in simple ratios to form compounds
Atoms are neither created nor destroyed
- Atoms cannot be destroyed, they simply rearrange in a chemical change, therefore the total amount of atoms remains the same

18. John Dalton (1800’s)

19. J.J. Thomson (1897) He created the “plum pudding model” of the atom.
Discovered the electron
Worked with Cathode Ray Tubes
Discovered particles with a negative charge, electrons – knew they were negative charges by the deflection of the beam from a magnet
He also was able to estimate that the mass of the electron was equal to about 1/1800 of the mass of a hydrogen atom.
His discovery of the electron won the Nobel Prize in 1906.
He created the “plum pudding model” of the atom.
“Pudding” is positive
Electrons are embedded within the “pudding”

20. J.J. Thomson (1897)

21. J.J. Thomson (1897)
Discovered that the beam going between the anode and cathode could be deflected by bringing a magnet close to the cathode ray tube. The deflection that Thomson observed showed that the beam must have been made up of negatively charged particles
He showed that the production of the cathode ray was not dependent on the type of gas in the tube, or the type of metal used for the electrodes. He concluded that these particles were part of every atom.

22. Robert Millikan (1909)
measured the charge of an electron using the oil drop experiment.
x-rays gave the oil a negative electron
1.60x10^-19 coulomb is the charge of an electron
using Thomson’s charge to mass ratio, he determined the mass of the electron is 9.11x10^-28g

23. Oil Drop Experiment

24. Ernest Rutherford (1911) Born in New Zealand 1871-1937
Tested Thomson’s theory of atomic structure with the “gold foil” experiment in 1910.
Bombarded thin gold foil with a beam of ‘alpha’ particles.
If the positive charge was evenly spread out, the beam should have easily passed through.
All of the positive charge and most of the mass of an atom are concentrated in a small core, called the nucleus.
Gold Foil Experiment (alpha scattering)
he determined that an atom’s positive charge and most of its mass was concentrated in the core (most of the atom is empty space)
he named the core “the nucleus”

25. Rutherford’s Gold Foil Experiment

26. Rutherford’s Model of the Atom
Contained a positive nucleus
Electrons were around the outside of the nucleus

27. Niels Bohr (1914) Start of the Quantum Mechanical Model
Electrons are particles
Electrons occupy different fields or energy levels
Based on the fact that atoms appeared to release fixed amounts (quantized) of energy when exposed to heat
When an electron is exposed to an energy source, it jumps to a higher energy level
When the electron eventually falls back to its original position, energy is released

28. Niels Bohr (1914)

29. Werner Heisenberg Principle of uncertainty
We cannot know both the location and the momentum of an electron
The more we know about an electron’s position, the less uncertain we are

30. Erwin Schrödinger (1926)
Based on Heisenberg's principle of uncertainty
Shows where electrons will probably be found by using the waves they leave behind
Electrons are waves
Update to the Quantum Mechanical Model
Sometimes called the Electron Cloud Model

31. Erwin Schrödinger (1926)

32. Exit Ticket
Write two facts that you learned today about a scientist that another group member researched

33. Exit Ticket
What does this activity teach us about the nature of scientific knowledge?