Teacher Notes
Summary
Groups of students will perform short-term research projects on the scientists who contributed to the development of atomic theory and share their findings with the class. Students will present their information using Microsoft PowerPoint. To facilitate the short-term aspect of this project, students are given a selection of pictures and movies to incorporate into their presentations. Time frame: 10-15 minutes to choose scientists, 1 block/2 periods for work day(s), 45-60 minutes for presentations.
Chemistry Concepts: history of atomic theory, technology integration
Materials
Handouts (see student file):

Atomic Theory Timeline instructions

Atomic Theory Timeline grading sheet

Atomic Theory Timeline Lecture Handout

Atomic Theory Timeline Quiz
Other Materials
 computers loaded with Microsoft PowerPoint (one per group)

Atomic Theory Timeline folder (contains template slides, pictures, and movies)

Atomic Theory Timeline Song file (PowerPoint)
 research resources – textbooks, Internet, etc.
Procedure Notes
At the end of one class period, have students form groups and choose a scientist. For homework, have them begin researching their scientist using their textbook and the Internet.
Before the work day(s), copy the entire Atomic Theory Timeline folder to the Desktop of each computer or to a network folder, if available. You might want to change the location where students will save their files since 3½" floppy disks can “go bad” causing the loss of a file. As an alternative, you could have them save directly to the Atomic Theory Timeline folder. WARNING: If a computer is loaded with Deep
Freeze, anything saved to the Desktop will be lost on Shut Down or Restart. Therefore, if the computer locks up and you’re forced to reboot, those files saved on the Desktop would be lost. That is why the instructions use 3½" floppy disks despite their potential pitfalls.
The scientists included in this timeline are: Democritus/Aristotle, Alchemists, Dalton, Becquerel,
Thomson, Millikan, Rutherford, Bohr, Schrödinger, and Chadwick. As the teacher, you may choose to omit some of these or cover them yourself. Democritus/Aristotle and Alchemists are easily covered as an introduction.
A set of three slides has been prepared for each scientist. The first slide contains his name and picture with space for a short bulleted list summarizing key information. The remaining slide(s) can be used to show pictures of atomic models and movies of experiments (both available in the Atomic Theory Timeline folder). All slides have the same format so they can be compiled into one uniform presentation.

Teacher Notes
The Atomic Theory Timeline folder contains 10 pictures and 5 movies. Students need to browse all of the options in order to determine which pictures and/or movies are appropriate for their scientist. The following table shows which items were intended for each scientist.
Scientist
Dalton
Becquerel
Pictures (description) atom_pic2.jpg (billiard ball model) atom_pic5.jpg (types of radiation)
Movies (description) atom_movie1.avi (separation of

,

,

)
Thomson
Millikan atom_pic4.jpg (plum pudding model)
Rutherford atom_pic7.jpg (plum pudding vs. nuclear) atom_pic10.jpg (nuclear model) atom_movie2.avi (cathode ray tube) atom_movie5.avi (oil drop experiment) atom_movie3.avi (gold foil experiment)
Bohr atom_pic6.jpg (bright-line spectrum) atom_pic8.jpg (Bohr model/spectrum) atom_pic3.jpg (planetary model)
Schrödinger atom_pic9.jpg (electron cloud model)
Chadwick atom_pic1.jpg (neutron model) atom_movie4.avi (planetary model)
Compile the final presentation for each class the day before the presentations will be given:
1.
Open the Atomic Timeline Presentation file in the Atomic Theory Timeline folder. Sample slides have been provided for a few of the scientists that you might want to cover. Delete these slides if they will be covered by students.
2.
Insert each set of student slides in chronological order: From the Insert menu, choose Slides from
Files . Browse to find the appropriate file. Either click Insert All or select the individual slides you wish to insert and click Insert . Repeat until all scientists have been inserted.
3.
From the File menu, choose Save As
. Give the file an appropriate name (e.g. “Timeline – Period 1”) and save it in the Atomic Theory Timeline folder. NOTE: Each class’ presentation MUST be in the
Atomic Theory Timeline folder with all the movie files or PowerPoint will not be able to play the movies during the presentation.
Before the presentation, distribute the Atomic Theory Timeline Lecture Handout to facilitate note-taking.
Each group will present in chronological order. Follow the presentations by singing the Atomic Theory
Timeline Song as a class (to the tune of the Alphabet Song/Twinkle, Twinkle Little Star). The Atomic
Theory Timeline Quiz may be used for assessment purposes.
PowerPoint Help
Inserting pictures:
1.
From the Insert menu, choose Picture > From File .
2.
Browse to the Atomic Theory Timeline folder. You should be able to preview each picture.
Choose the desired picture and click Insert .
3.
Drag the corner of the picture to change its size while maintaining correct proportions.
Inserting movies:
1.
To preview movies, open the Atomic Theory Timeline folder and double-click on each movie to view it. Return to PowerPoint to insert the desired movie.
2.
From the Insert menu, choose Movies and Sounds > Movie from File .
3.
Browse to the Atomic Theory Timeline folder. Choose the desired movie and click OK .
4.
When asked if you want your movie to play automatically, click No . This will allow more control over starting and stopping the movie during the presentation. Simply move the cursor over the movie (turns into a hand) and click to play. Clicking again will alternate between pause

Teacher Notes and play. NOTE: The cursor (hand) must be over the movie. Otherwise, clicking will cause
PowerPoint to advance to the next slide.
5.
Drag the corner of the movie to change its size while maintaining correct proportions.
As stated in the student instructions, it is recommended that animations, sounds, etc. be kept to a minimum.
Scientist Data Chart Answer Key
SCIENTIST
Dalton
Democritus
EXPERIMENT
N/A – Philosopher
Based on others’ experiments
Uranium Salts
THEORY / DISCOVERY
All matter consists of tiny particles called atoms.
Billiard ball model – atoms are uniform, solid spheres.
Becquerel
Thomson
Millikan
Rutherford
Cathode Ray Tube
Oil Drop Experiment
Gold Foil Experiment
Discovered radioactivity when uranium spontaneously developed photographic film.
Three types:

(+),

(-),

(neutral).
Discovered negatively charged electrons.
Plum pudding model – negative electrons dispersed throughout a positive sphere.
Calculated the charge and mass of the electron.
Discovered dense, positively charged nucleus.
Nuclear model – dense positive charge (nucleus) surrounded by negative electrons
Bohr Bright-line Spectrum Discovered energy levels.
Planetary/Bohr model – electrons travel in specific, circular orbits around the nucleus.
Schrödinger
Chadwick
Wave Equations (math) Calculated the probability of finding electrons in regions called orbitals.
Electron cloud/Quantum model – electrons move within orbitals (not specific, circular paths).
Joliot-Curie Experiments Discovered neutrally charged neutrons within the nucleus.
Neutron model – added neutrons to the nucleus to account for additional mass.
The key for the Atomic Theory Timeline Quiz follows.

Teacher Notes
Name Key Class Date
1.
Draw a diagram representing the atomic model developed by Rutherford. Be sure to LABEL ALL
IMPORTANT COMPONENTS INCLUDING CHARGES.
RUTHERFORD
Match the experiment or discovery on the left with the appropriate scientist on the right.
H 2. Developed the electron cloud model of the atom.
E
F 4. Calculated the mass and charge of an electron.
I
D 6. Proposed that atoms were uniform spheres.
A
3.
5.
7.
First proposed the concept of the atom.
Discovered negatively charged electrons.
Discovered radioactivity.
B 8. Stated that electrons move in circular orbits.
A.
Becquerel
B.
Bohr
C.
D.
Dalton
E.
Chadwick
Democritus
F.
Millikan
G
C
9. Discovered a dense, positively charged nucleus.
10. Proposed the existence of neutrons.
G.
Rutherford
H.
Schrödinger
I.
Thomson
11.
Number the following models in chronological order, starting with 1 for the earliest model.
1 Billiard ball model
6 Neutron model
5 Electron cloud model
3 Nuclear model
4 Planetary model
2 Plum-pudding model
BONUS: Name the experiments performed by the following scientists.
(1) Millikan: Oil Drop Experiment
(2) Rutherford: Gold Foil Experiment
(3) Thomson: Cathode Ray Tube Experiments