PHYSICS 444/544: ADVANCED LABORATORY
Fall 2011
Jed Brody and Horace Dale
The purpose of this course is to broaden and refine your laboratory and analytical skills, to further your mastery of several fields of physics, and to communicate your results in written reports that are clear, concise, and complete. You will choose four of twelve available projects, grouped by topic:
ANALOG ELECTRONICS
Transistors: Study the properties and applications of bipolar junction transistors. Construct emitter followers, amplifiers, and a current source.
Op
amps: Study the applications and
limitations of op amps. Construct
amplifiers, differentiator and integrator circuits, and a current source.
Chaos in electronics: Construct circuits that exhibit the Lorenz
attractor and other chaotic phenomena. Prerequisite: op amps, either in this course or previously.
SOLID-STATE PHYSICS
Transient heat conduction: Use laser beam-bending to measure and analyze the "cold front" passing through a material dipped in ice water.
Hall
effect: Fabricate silicon and
copper Hall devices and measure Hall voltage and carrier density and type. Optional: if you do transistors or op amps before Hall
effect, you can build your current source yourself!
LED statistical mechanics: Observe the Boltzmann distribution in LED emission spectra. Optional: if you do transistors or op amps before LEDs, you can build your current source yourself! And if you also choose Hall effect, do Hall effect before LEDs.
X-ray physics: Investigate X-ray emission, absorption, and scattering.
CLASSICAL MECHANICS
Rotary pendulum: Observe natural frequency, damped oscillations, resonance response, period doubling, and chaotic attractors in the motion of a rotary pendulum.
Collisions (written by Phil Segre): Construct a digital circuit to determine the durations of collisions between metal spheres and a plate.
Water-column oscillations: Predict and measure the frequencies of oscillating water columns.
ASTRONOMY
Variable stars: Observe and analyze the light curves of variable stars.
Radio astronomy: Use the satellite dish newly reconfigured as a radio telescope.
You will write lab reports for three of your four projects. Electronic submissions are welcome.
Since the refinement of written communication is a major goal of this course, you will have the opportunity to rewrite each lab report. The grade for the revised report will replace the original grade only if the new grade is higher, so you have nothing to lose.
Grades are determined as follows:
10 points Class participation (attendance and lab notebook).
90 points Three lab reports (30 points each)
For safety, please do not wear open-toe shoes in the lab. Liquid nitrogen is used in some of the experiments.
Please do not hesitate to contact us if you'd like help understanding any experimental principles or procedures. That's why we're here.
Jed Brody
N308, 7-5580
Horace Dale
N218, 7-4007
INTRODUCTION
August 24. Electronics tutorial (part 1).
August 30. Project selection. Electronics tutorial (part 2).
PROJECT 1
August 31
September 6
September 7
September 13
September 14
September 20
PROJECT 2
September 21. Lab Report 1 due at beginning of class.
September 27
September 28. Lab Report 1 returned.
October 4
October 5. Lab Report 1 (revised) due at beginning of class.
October 12
PROJECT 3
October 18. Lab Report 2 due at beginning of class.
October 19
October 25. Lab Report 2 returned.
October 26
November 1. Lab Report 2 (revised) due at beginning of class.
November 2
PROJECT 4
November 8. Lab Report 3 due at beginning of class.
November 9
November 15. Lab Report 3 returned.
November 16
November 22. Lab Report 3 (revised) due at beginning of class.
November 23. No lab (Thanksgiving Eve)
November 29
CONCLUSION
November 30. Lab Report 4 due. Course evaluations.
December 6. Lab Report 4 returned in individual conferences.
December 13. Lab Report 4 (revised) due.
Guidelines for Writing Lab Reports
Your report should consist of six sections.
1. The abstract is a single short paragraph that summarizes the report. It gives the main objectives and conclusions of the experiment. Specific, quantitative results must be included. Many readers of scientific papers read only the abstracts and the figure captions before deciding whether the whole paper is worth reading. The abstract is sometimes in the present tense, never the future tense. I've often written my abstract by copying the conclusion section, rephrasing it a little, and adding an introductory sentence in front.
2. Introduction. This section introduces all the theory that the reader will need to understand the subsequent sections. Any equations that you'll use are given here with qualitative descriptions. If you like, you may briefly discuss the historical background and importance of the experiment.
3. Procedure. This section contains a description of the experimental process. In principle, someone should be able to reproduce your experiment after reading this section. The procedure, unlike the lab manual, is always in third person, never second person (including imperative). If appropriate, you may refer to the manual, but the reader should have a general understanding of what you did without turning to the manual.
4. Results. This section is for your experimental data tables and all other unprocessed data collected during the experiment. Detailed discussion of the data is not desired in this section.
5. Analysis and discussion. In this section, the theory from the introduction is applied to your own data. Manipulation of the data from the results section is presented here. Graphs showing functional relationships among experimental parameters are usually the best way to present your findings.
6. Conclusion. Was the objective of the experiment obtained? If your job was to measure some physical parameter, what is the value? Was the purpose of the experiment to test some theory? Does your work support the theory or not? How do your results compare with accepted values? Are your results trustworthy?
Your lab report will be graded with the following in
mind:
Understanding: Do you correctly explain the physics underlying the experiment?
Completeness: Have you left out anything?
Clarity: Is your report clear and to the point?
Accommodate your reader: Good scientific papers accommodate both the "lazy reader" and the "thorough reader":
- The "lazy reader" reads only the abstract and the figure captions. All the evidence that you've accomplished something interesting should appear in the abstract, figures, and figure captions. The abstract should stand on its own and make sense to someone who hasn't read the rest of the paper. Each figure with its caption should similarly make sense to someone who hasn't read the rest of the paper.
- The "thorough reader" (possibly a "lazy reader" impressed by your abstract and figures) wants to read a continuous narrative from start to finish. This reader will ignore your figures and tables until the text refers to them; you should guide your reader to each figure and table whenever you want your reader to look there.
Placement of captions: Figure captions go below the figure. Table captions go above the table. (This is an arbitrary but universal rule; check any journal.)
Spelling and grammar: Proofread.
Most common grammatical error: Run-on sentences (specifically, comma splices, which are common in informal writing but inappropriate in scientific papers).
INCORRECT: I love writing lab reports, I weep at the beauty of my work.
CORRECT: I love writing lab reports; I weep at the beauty of my work.
CORRECT: I love writing lab reports, and I weep at the beauty of my work.
CORRECT: I love writing lab reports. I weep at the beauty of my work.
Another common grammatical error: Not knowing the difference between "its" and "it's."
Plagiarism: Plagiarism is a violation of the Emory Honor Code. You are expected to write your laboratory reports on your own. Any unique phrases lifted directly from any source, including the internet, must be enclosed in quotation marks with the source clearly identified. All sources that you studied to gain understanding while preparing to write your laboratory report, including links to the internet, should be listed at the end of your report under References. If you are ever in doubt, identify the source of your material. In particular, be sure to cite the source of any graphics you download into your report.