History of the Atom Webquest

Introduction

All matter is made of tiny particles called atoms. These atoms are so small that, in order to begin to see the atoms that make up a drop of water — we would have to blow it up to a size of 15 miles across! These atoms are in turn made of even smaller particles called protons, neutron and electrons.

Everything that matter is and everything that matter does can be explained by the behavior of atoms!

How have scientists come to understand these particles we cannot see? How has this understanding changed and evolved over time? And what remains to be discovered? In a way, the scientists who have unraveled the properties of the atom have been like detectives solving parts of a mystery — with new mysteries arising out of every discovery.

Your Task

You will work as a class to research the scientists and experiments that have lead to our current understanding of the atom and its properties. You will work in a group assigned to one of five tasks. Within each group you will research, and report on, the following-

1. Biography: When did this scientist live? What was his or her education and background? How did the views of the scientific community influence their views and work?
2. Discovery: What discovery is this scientist noted for? Thompson, Rutheford and Millikan are each noted for a landmark experiment — what was it and what did it prove?
3. Timeline: How did this discovery change our view of the atom or its properties? How did it influence future research?

Each group will prepare a 10-15 minute presentation to the class with the results of their research. You may use posters, demonstrations or any other visual you choose.

You must divide the tasks so that all group members have a specific role in the research and the presentation. Active participation by all members of the group is required in order for the group to receive full credit for the assignment.

Each group will prepare a single poster to contribute to a class timeline of the discovery of the atom. Each poster in the timeline will note the date or period of the discovery, the major character and the advancement in our understanding of the atom that is associated with your assigned topic. Together, these posters should present a history of the atom.

Finally, each group will prepare a report of their research on the biography, discovery and timeline of their topic. This report should be about three pages — so about one page (plus or minus) should be devoted to each topic. Just hit the major points! This task may (and should) be divided between group members — but you must make the final product look like a single report — not a cut and paste of three reports.

A note on sources: All sources must be cited. Your report must cite at least two sources and include a bibliography.

Resources:

The following resources should get you started. Questions in each area are provided as guides — your report should answer these questions. In addition, use search engines on the internet to find additional data and the hard copy resources available through the media center.

Each group should review the following sites:

A discussion of the scientific process as detective work:

http://www.owlnet.rice.edu/~chem121/class/chemproj/typereasoning/holmruth.htm

A timeline of the atom:

http://www.watertown.k12.wi.us/hs/teachers/buescher/atomtime.asp

Sites and guidelines for your task:

1. Early History of the atom:

http://www.watertown.k12.wi.us/hs/teachers/buescher/atomtime.asp

http://www.chem.ualberta.ca/courses/plambeck/p101.new/p01021.htm

(Information on John Dalton and his theories)

What were the views of the Greek philosophers ideas of theories? What is the difference?

http://www.owlnet.rice.edu/~chem121/class/chemproj/typereasoning/holmruth.htm

(see Holmes and Rutheford for a good analysis of theory vs. opinion)

What were John Dalton’s theories? How did he arrive at his conclusions? What is the significance of Dalton’s work?

For this task do the biography of John Dalton only and focus on how he changed our view of the atom.

2. Rutheford and the Atomic Nucleus

http://micro.magnet.fsu.edu/electromag/java/rutherford/

http://dbhs.wvusd.k12.ca.us/AtomicStructure/Rutherford-Model.html

http://www.watertown.k12.wi.us/hs/teachers/buescher/atomtime.asp

(Applet showing gold foil experiment conducted by Geiger and Mardsen)

Describe the gold foil experiment? What did Rutherford expect to see?

Why did the results surprise Rutheford? How did this experiment change the view of the atom developed by Thompson?

3. Thompson and the discovery of the electron

http://www.aip.org/history/electron/

http://www.watertown.k12.wi.us/hs/teachers/buescher/atomtime.asp

http://webserver.lemoyne.edu/faculty/giunta/thomson1897.html

http://dbhs.wvusd.k12.ca.us/AtomicStructure/Thomson-Model-Intro.html

What experiments did Thompson conduct? What was he investigating?

What hypothesis did Thompson develop based on his experiments?

What was Thompson’s model of the atom?

Why were Thompson’s results controversial?

What further research was needed?

How has our understanding of the electron changed since Thomson and Millikan?

4. Robert Millikan’s Oil Drop Experiment

http://www.nobel.se/physics/laureates/1923/millikan-bio.html

http://library.thinkquest.org/19662/low/eng/biog-millikan.html

(Biography of Robert Millikan)

http://dbhs.wvusd.k12.ca.us/AtomicStructure/Determine-electron-charge.html

http://www.bun.falkenberg.se/gymnasium/amnen/fysik/millikaneng.html

What was Millikan’s experiment? Did his experiment support the theory of the electron?

How did Millikan’s experiment solve the problem that Thompson could not?

How has our understanding of the electron changed since Thomson and Millikan?

5. Marie Curie, Henri Bequerel and Radioactivity

http://www.accessexcellence.org/AE/AEC/CC/historical_background.html

http://www.nobel.se/chemistry/laureates/1911/marie-curie-bio.html

http://www.watertown.k12.wi.us/hs/teachers/buescher/atomtime.asp

http://www.aip.org/history/curie/resbr1.htm

What radioactive element did Bequerel discover?

How did Bequerel observe the property of radioactivity?

Who was M. Curie’s research partner?

What radioactive elements did M. Curie discover?

What is radioactivity?

How can an element change its identity?

What is a half-life?

For a biography choose either Bequerel or M. Curie

More General References:

http://www.woodrow.org/teachers/chemistry/links/chem1/Chapter3.html

http://library.thinkquest.org/19662/low/eng/main.html

Grading for History of the Atom This task will comprise the project portion of your grade for term 1. Most of the grade will be given based on the group’s work. A final 10 points will be given for full individual participation with up to 10 points of extra credit given for extraordinary individual participation. Individual grades will be given based on contributions observed during class work on this project, during the presentation and through question and answer sessions with group members. Group extra credit will be given for creativity in research or presentation above and beyond the call of duty.