1. “The secret of getting ahead is getting started.”
Do Now
When the bell rings
After the bell (2 min)
In your seat:
With pen/pencil
With Notebook
With Handout (from last class)
Silent and ready for Do Now
Respond to the following:
“The secret of getting ahead is getting started.”
-Mark Twain
Still needs Do Now

2. Agenda  Do Now (5 min) Announcements/Test Scores (5 min)
Reflection (5 min)
Remediation Topic (5 min)
Warm Up (5 min)
Highlights of atomic theory history (20 min)
Theory v. Law (5 min)
Independent Practice (10 min)
Exit Slip (5 min)
Closing (2 min)
Agenda

3. Remediation Topic: How? What?
C – None
H – Raise hand
A – Identifying Lab Equipment
M – None
P – Answering questions to the right, recording responses on left page, discussing with group each prompt
Identify the use of each piece of lab equipment (use your reference sheet to guide you)
Graduated cylinder
Erlenmeyer Flask
Graduate beaker
Tongs
Dropper

4. The History of the Atom Day #2
Objectives:
Differentiate between theory and law
Understand the history of the atomic theory
Create a timeline that shows the changes in the atomic theory over time
Summarize the results from Rutherford’s experiment and identify the role of the cathode ray in the discovery of the atom

5. Warm Up How? What? (5 min) Dalton Chadwick Thomson Bohr Rutherford
C – Whispers
H – Raise hand
A – Answer with group,
M – None
P – Record responses on reverse side of page.
Using your notes from last class place the following list of key contributors to atomic theory in order of appearance
Dalton
Chadwick
Thomson
Bohr
Rutherford
Schrodinger
Heisenberg
Milliken
Democritus
de Broglie
Seaborg

6. Our Timeline 1941-1951: Seaborg discovers transuranium elements
400 BC:
Democritus theorizes the concept of “atomos”
1911:
Rutherford’s Gold Foil Experiment (+ nucleus)
1930:
Schrodinger’s wave model
1897:
Thomson’s Cathode Ray Tube (electron)
1923:
De Broglie discovers wave nature of electrons
1909:
Millikan’s Oil Drop Experiment (electron is negative)
1927:
Heisenberg’s Uncertainty Principal
1803:
John Dalton’s atomic theory
The Father of Modern Atomic Theory
1932:
Chadwick discovers Neutron
1922:
Bohr’s Model

7. What Is An Atom? Watch the following video: Answer the following:
Bill Nye
Answer the following:
If atoms are mostly empty space, why don’t they break when we stand on them?
What is in the nucleus? How far are electrons from the nucleus?
What do you get when you combine atoms?
How can you demonstrate the spaces between molecules of water?
What Is An Atom?

8. Putting it Together 4 Key Components we need to understand
Law of Definite Proportions
Rutherford’s experiment
JJ Thomson’s Cathode Ray Tube Experiment
Continuous Development
Putting it Together

9. Law of Definite Proportions
Also known as Proust’s Law
Definition: When two elements combine to form a compound, they do so in a definite proportion by mass.
Ex: H2O = 2:16  1:8
Mass of Hydrogen: 1 amu x 2 (2 atoms of H)
Mass of Oxygen: 16 amu
Law of Definite Proportions

10. JJ Thomson’s Cathode Ray Tube
Cathode Ray Tube Experiment
Discovered the electron
JJ Thomson’s Cathode Ray Tube = =

11. Rutherford’s Gold Foil Experiment
Discovered the positively charged nucleus
Rutherford Animation
Rutherford’s Gold Foil Experiment
Prediction
Reality

12. Continuous Development
Science builds upon discovery
Every new development in our understanding came by building on or disproving a previous model
Our atomic model is only built on 200 years of science
It is not complete (see Quarks)
Continuous Development

13. Activity: Independent Practice
How?
What?
10 minutes  Discuss for 5 minutes  Verify & Review
All rows and columns add up to the same number
C – None
H – Raise hand
A –Answering questions about atomic theory history
M – None
P – Recoding answers on provided page, head up, reading and thinking through all questions, discussing with group

14. Exit Slip How? What? (5 min)
C – No talking
H – Raise hand
A – Taking exit slip
M – In seat
P – Completing exit slip without notes and turning in
If you finish early, summarize what you learned at the bottom of your notes OR answer today’s guiding question

15. Forgetting to stretch is a bear.
Closing
What are 3 key takeaways from today and yesterday?
Complete the 4 Stretch questions
Be ready to discuss the structure of the atom next class