Physics 128, Advanced Experimental Physics, Spring 2018

Physics 128 Staff

Note - all info preliminary and subject to further refinement.


You can click on the image of the table below, which takes you to the google spreadsheet where the assignments are tracked; from there, you can find links to each experimental writeup.

You can click on the image of the table below, which takes you to the google spreadsheet where the assignments are tracked; from there, you can find links to each experimental writeup.

In Physics 128L, you will work through a set of modern physics experiments. The main goal is to learn how to imagine, perform, and report experimental physics results.

Course Information and Material

  1. A calendar for the course appears above. There will be a mandatory lecture at the first meeting of the course.

  2. The primary information/text for the course - the lab writeups - are here.

  3. ASAP, no later than 11:59pm on Thursday, 6 April for MW section, and and no later than 11:59pm on Friday, 7 April for the TuTh section, sign up for your laboratory choices:

  4. You will be assigned lab partners... labs are done by pairs (and sometimes threesomes) of students. Everyone cannot get their first choice, and the staff will do their best to make a fair assignment by the end of the first week.

  5. Get a lab notebook - you will need an official lab book (or two) for the course. Use lab books available at the UCSB bookstore. This photo shows the possibilities. We recommend the one on the right, it is a 100-page lab book where each page has a carbon duplicate, for $20. The non-preferred option is to purchase two of the books on the left, which is twice the cost, but gets you three times the number of pages. Keeping a good lab notebook is a major skill you must learn in this course; carbons each partner's notebook must be turned in for grades. The key concept in notebook keeping: can both you, and an attentive and knowledgeable second party, reconstruct your work? (if you purchase two non-carbon books, you will use the second while the first is being graded).

  6. You and your partner must:
    1. Each prepare a brief whiteboard presentation ready to give on the first lab day for a new experiment; you may not be asked to give the presentation until a subsequent.
    2. Each partner will be chosen at random to give a <5 minute presentation during the first 30 minutes of each of the 4 workdays. Every person enrolled must give a presentation for each experiment. You will receive a grade from 0 through 3 on the presentation.
    3. The lab preparation work (background for the whiteboard presentation) must be entered in your lab notebook prior to the first lab meeting. You will receive a grade from 0 through 2 on this work. You can correct your work and get some credit back when you turn in the lab notebook for grading.

  7. Learn to use data analysis software. Please use Wolfram's Mathematica. It is installed on all lab computers, many UCSB computer-cluster computers, and in the PSR. For your own computer, UCSB offers a student license. There is a pretty good tutorial, a little dated now, but good on the basics, here. Spreadsheets are extremely useful for preliminary work, but might not provide all the capabilities you need. We have a directory of useful Mathematica notebooks for Physics 128.

  8. Use one of two texts on error analysis: Bevington and Robinson and Taylor. The core of experimental research is constant attention to important errors on the quantities you are measuring, and then on the propagation of errors to the parameters you are deducing from your experiment. Note the important errors on numerical quantities you record in your logbook. Often the error on independent variables or "instrument settings" is negligible, and need not be noted, but you do well to mentally imagine what the error is on those as well. The texts linked help greatly on propagating errors on your recorded quantities to the parameters you deduce from the experiment.

  9. Learn to use a scientific word processor to write-up the report that describes your work. Four reports will be required, and lab partners turn in one report, in addition to the turning in of lab notebooks. We strongly suggest that you use LaTeX on Overleaf, where accounts are free. We have an example report that you may use to learn the format and technical details. We've posted a brief summary to the formatting commands here. Once you have an Overleaf account, you can copy this example into your directory space. Please give yourself extra time to learn to use this word processor... it is not trivial, and most scientific reporting uses it. Reports must be brief and to the point. Longer analysis to support the brief lab report must be written in the lab notebook. The lab notebooks will also be used to assess if work was shared fairly between lab partners.

Grading and Flow

Over your four lab days available to complete your work on an experiment; you will do two experiments.
  1. On day 1 of a new lab, you and your partner will show up, having read the lab, done the pre-lab work in your lab notebook, and be prepared go to the board and give a very brief description of the lab and what you will do. This talk should give the principle of the experiment, present some mock data for one of the key measurements, and present an error analysis for that measurement. Terseness is necessary, and going too long will lower your grade. You will be asked questions that will contribute to the grade.

    The talks will be 10% of your overall course grade

  2. On days 1-4, you will work independently on the labs, keeping all of your data/procedures/observations/comments in a professional-style lab notebook. The staff will circulate to help you. Attendance is required, first, because your labmates expect you to work as a team, and second, because we're paying attention.

    The notebook is worth 40% of your overall course grade. You must also record the work to analyze your data outside the laboratory, in preparation for your report, in your lab notebook.

    Rubric for lab notebook portion:

    1. 10 percent of - clarity, neatness, order; recording dates experiment done, lab partner, etc.
    2. 20 percent - lab prelab and work required in lab manual(s)
    3. 30 percent - clear raw data, computed quantities, and results
    4. 30 percent - error discussion and analysis
    5. 10 percent - conclusions and outlook (possibly, discussion of incompleteness or malfunctions)

  3. On roughly first day of the next block (because of the holidays this quarter, there is some variation recorded in the schedules above) you must hand in the previous block's notebook page carbons, plus your short report.

    The reports combined are worth 50% of your overall course grade. The grading breakdown for the report is here.

  4. Important: an earnest pre-lab, notes in the lab notebook, and solid writeup with final values that are off from final "textbook" numerical values will generally receive a higher grade than sketchy pre-lab, lab notes, and writeup with perfect final numerical values. Indeed, it will be possible to get an "A" with final numerical values that are somewhat far off from the "textbook", if there is an excellent discussion of errors, and, perhaps, the errors that caused the measurements to differ from the "textbook".

  5. For the first of the two labs, your report will be graded strenuously, and if the grader requests, you must will be asked to re-submit the report one week after it is returned.


There are important safety issues in any lab work, of which you must be aware. Some examples of safety hazards are intense light sources (lasers and gas discharge tubes), electrical hazards (high voltage or current), radiation sources (radioactive substances or X-ray machines), extreme temperatures. I require that you start each experiment by doing an assessment of the safety issues. You will need to take steps to carry out your experiments safely; this is part of acting like a professional experimentalist. For example:

Important safety rules that everyone must follow are:

Last revision, 04/04/2018, Harry Nelson