Physics 192 consists of a series of experiments in optics and modern physics.  The experiments are all described in the laboratory writeups (available as pdf files through the links below) and you are expected to read the material and prepare yourself before coming to class as there will not be sufficient time to start from scratch during the three hour laboratory session.  The laboratory period for new experiments will start with you handing in the introduction portion of the lab report (see below for more detail).

You will do the experiments in groups of two.   You may collaborate with your partner in data taking, but you are expected to do independent calculations and write independent reports.

The reference for this course is "An Introduction to Error Analysis" by John R. Taylor, published by University Science Books. Readings and sample problems will be assigned from this text. The sample problems are selected to help you prepare for the error calculations needed for the week's lab, and will have answers provided so you can check that your technique is correct. The actual error calculations for your lab report will be turned in along with each lab report, and will count for 20% of your grade. The lab instruction manual, the sample problems and this syllabus are on the web at: . There is no coursepack; download and print from the web site.


During this course, we expect you to:
* to become familiar with some laboratory experiments and procedures.
* to make careful and critical measurements.
* to record and organize your observations.
* to estimate uncertainties in your measurements and to use them to judge whether your measurements are consistent with previous measurements or standard values.

Before each class, you will be expected to read the description of the experiment and read sections of the book by Taylor to clarify how to perform the necessary error estimations.  This advance preparation is essential if you wish to successfully finish the lab successfully.  Your laboratory measurements will be performed during class.  You should also perform calculations during class to determine whether your measurements are valid.  If you blindly take data without checking it, your grade will suffer.

This class assumes you have learned certain skills from PHY191: using Kaleidagraph, using Excel with formulas, performing a General Fit in Kaleidagraph, performing uncertainty calculations, making error bars in Kaleidagraph, choosing an appropriate number of signficant figures, calculating the significance of a deviation from expectations by the "t-value", and using summary tables to organize and summarize your results.


The Lab Notebook:  You must purchase a lab book for this course. Note that this must be a lab notebook, i.e. with an x-y grid of lines, bound or spiral, but not a looseleaf notebook. If you have an old lab notebook from a previous class that still has unused pages, it is fine to use that. There should be a page number on each page of the lab book (by hand if necessary), and pages should never be removed from the lab book. Your lab book should record your procedure as well as your results. All your work should be in the lab book - including any mistakes or duplicate measurements. In other words, your lab book is a recording of the procedure that you went through including, any false steps. You should be able to reconstruct for any given day what you did. The lab book should especially explain your choices on procedure which were not specified for you in the lab handout.False steps should be neatly crossed out and a note should be recorded in the lab book indicating the nature of the mistake. This is the method used by practicing scientists for the recording of their experimental measurements. If you felt your bad data was caused by following directions in the lab writeup, be sure to point out the problem area in your lab report.

The lab book should also contain:
- on the first page for this lab session, the name of the experiment, your name, your partner's name, and the date
- Rough sketches of apparatus
- identifying information (table number, sample code, for example) which will allow your instructor to determine the equipment and sample material used in your experiments.
- Answers to questions posed in the lab writeup intended to be answered before measurement
- a sketch of how you measured something, if it's not just reading a dial
-all your original data (write it in the book, rather than typing directly into a spreadsheet, unless a computer is directly producing the data file
- Estimates of errors in measurements, and why you chose this estimated uncertainty.
- “on the fly” calculations to assess quality of data

Using the experimental data taken during the lab period, you will prepare a lab report to be handed in, along with photocopies of the relevant lab book pages containing the data, at the beginning of the next week's lab.  

You will analyze your data in excel. Here is a sample spreadsheet showing you how to organize uncertainty calculations, and a sample summary table for your lab report.

The lab report should “tell a story”: explain what you did, and what you concluded from your work. Your report should be a short scientific paper readable by a peer: a student in your major who didn’t perform this lab but otherwise has same general background as you.  Writing lab reports at this level is practice in the kind of writing and analysis you would perform professionally on real research projects, just as keeping your lab book should build good habits for your scientific record keeping for real research projects. Here is a sample of a good lab report. This lab report shows a simple example of a page on uncertainty calculations; here is an example of a more complex set of calculations.

A blank lab report document is available as a .doc Word document. Start writing your lab report by downloading and modifying this document, which describes the report's organization and contents.

Three specific requirements:

1) write the introduction and bring it to class at the start of each new experiment

2) email your spreadsheets to your TA. Use a sensible name, like exp2_myname.xls .

3) photocopy the relevant pages from your lab book and turn it in as part of your report


A typical assignment of points for grading labs is given below to give you a feeling for the emphasis on different parts of the lab report.  For specific labs with particular emphases, the relative weights may be adjusted somewhat from this general guideline.

5      introduction            

5      procedure    

As the semester proceeds and you get better at writing the introduction and procedure, fewer points wil be allocated to these sections and more to the measurement quality, results, and conclusions.

12    lab book:

Goal: enough info so you can reconstruct what you did
Appropriate sketches, procedure choices; what did you measure
raw data, uncertainty assessment
check calculations or plots to test data quality

10   measurement quality
Goal is careful measurement
Accuracy of your final results will be compared with those obtained by the TA’s and those of other students
8   results, answers to questions
excel calculations and formulas used (and sample calculations if not using excel)
explanation of formulas you needed to derive
        (refer to lab book for derivation or sketch as needed)
graphs, possibly including fits, as appropriate
answers to questions posed in lab writeup, or by your TA

6 drawing conclusions
appropriate summary tables of key results and uncertainties: ( typically 3-4 points)

what can you conclude, based on your results? (typically 2-3 points)
use of uncertainties, t values to back up conclusions      
discussion of inconsistencies/possible systematic
constructive suggestions for improvement of lab writeup or procedure

4   miscellaneous:  
labeling of tables and graphs, units, significant figures,
spelling, grammar, coherent organization of lab report

10 Uncertainty Calculations


50 (lab) + 10 (uncertainty calcs)        

Attendance is mandatory.  If you have an excused medical absence, your instructor will determine whether you will be permitted to do a makeup or whether you will be graded on  the remaining 8 reports.


The lab writeups are available as pdf files from the links shown below.

Your grade will be based on the results of your experiments, on the quality of your reports and on a practical exam. Each lab will be graded on a scale of 0-50 (see rough point allocation above), and another 10 points will be allocated for the uncertainty calculations. The weighting of the reports (and uncertainty calculations) will be 1 for single-week lab reports, and 2 for 2-week labs. The lab reports form 70% of the grade, the uncertainty calculations 15% of the grade, and the practical exam 15% of the grade.

The instructor of each section will normally grade the work of students in their sections. The average grade will be approximately 3.0, for students of each instructor.


Week of



Jan. 10

Intro lab; print reference guide; buy lab book, text


Jan. 17

MLK day: no class


Jan. 24

Geometrical Optics


Jan. 31

Diffraction & Interference I


Feb. 7

Diffraction & Interference II


Feb. 14

Grating Spectrometer and diagram of controls


Feb. 21

Optical Activity (subject to change)


Feb. 28

Electron Charge and Mass I: e/m


Mar. 7

Spring Break


Mar. 14

Electron Charge and Mass II: e


Mar. 21

Introduction to Radiation


Mar. 28

Absorption of Radiation


Apr. 4

Half-Life Measurement


Apr. 11

The Compton Effect I


Apr. 18

The Compton Effect II


Apr. 25

In-Lab Practical Exam (15% of lab grade)