Physics 370 — Experimental Physics
(Ongoing Minor Revisions)
Spring 2017, Room 209 HWWE, MWF 2:20-5:20
Dr.
Alem Teklu Office: 210 JC Long, Office hours: MWF,
11:00-12:00
Building/Lab Access phone: 953-5609
Emergency phone: 953-5611
email me: teklua@cofc.edu
or send me an anonymous web-based email
Contents
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Reference Material
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Elements of a Good Experiment
- Safety
- Problem statement
- Literature search
- Design of the experiment
- Design of the equipment
- Execution of the experiment
- Maintaining records
- Analyzing your data
- Recognizing errors and their impact
- Communicating your results
Equipment review and introductions may include
- Circuits
- Power Supplies
- Multimeters
- Oscilloscopes
- Lock-in Amplifier and chopper
- Gamma spectrometer
- Electron Microscope
- Compact Optical Spectrometers
Computer Use
- Web resources
- Computer programs
- LaTeX—for document preparation
- Inkscape—for technical illustrations
- Mathematica—for data processing and graphics
- Other graphing programs
Data Analysis
- Formal analysis of errors
- Uncertainty
- Data fitting
- Data evaluation
Writing a Paper
- The audience
- Abstract
- Style
- Structure
- Tables and illustrations
- Equations
Ethics
General
There is no formal text for this
course, rather it is a compilation of notes, handouts, and web resource
materials. It is absolutely vital that you take comprehensive notes during the
class. This semester is your opportunity to develop your physical intuition in
the context of investigating a problem. You will get to formally state the
problem, design and construct the investigation, analyze the data, draw
appropriate conclusions and communicate the results. In all respects a more
polished performance is required of you in this class than you have had to
demonstrate in the past. This course represents a transition for you, from
student to professional. You need to develop a professional sense of
responsibility for the work you produce, and for the process of producing it.
Much of the evaluation of your work (by me) is from a professional perspective.
Think of yourselves as doing work for pay, and I am the boss. Don't turn in a
student product, turn in a professional one.
Please communicate your questions, comments, and problems to me. I am
pleased to see you any time you can drop in. Please leave me a note if you
can't find me.
It is your responsibility to learn—to do the work using available resources,
taking responsibility for finding the knowledge and equipment you need. You get
to work in groups and alone. Take this opportunity to show to everyone that you
can handle the responsibility. Historically, the biggest problem encountered by
students in this course is poor time management. You are given some freedom to
schedule your assault on the problem—don't abuse this freedom.
Be courteous to others. We have limited space and equipment, so don't
expect to set up an experiment and have sole use of the equipment and space for
more than a couple of days. You may need to coordinate with your classmates for
access to some equipment. There may be times when courtesy should be extended
with regard to opening the door and turning on lights. You are expected to put
equipment away and otherwise keep the experiment areas clean and tidy.
Preparation for the Course
Modern Physics (phys230) is a
prerequisite for this course. You will need to maintain a working knowledge of
the physics and mathematics at the level of physics 111/112/230. Laboratory
experiences in physics 111/112 are a valuable knowledge and experience base for
this course. Review your laboratory experience. Look over old reports to
identify skills you need. Of course by now you should have completed English
110. If you haven't, then don't take this course. Finish English first.
I also assume that you have computer skills, including email, using the web,
word processing, Mathematica, spread sheets, and other generic, scientific
computer tools. We will enhance your skills with all of these.
Structure
We will have formal classroom time, especially early in
the semester. It is important that you apply your attention to these
presentations as they will be vital to your experiments. Students will be
required to pick a professional track—physics, astronomy, or meteorology. While
everyone does the same first experiment, there are computational, equipment and
write-up differences between the professions.
There will be two phases to the course.
- Lab skills development and proficiency exercises
- Simple circuits/multimeters/power supplies/oscilloscopes/function
generators
- LaTeX, for document preparation
- Inkscape, for technical illustrations
- Statistics
- Curve fitting
- Error propagation
- Graphical representation of data
- Perform experiments and write reports
- e/m ratio for electrons—everyone does this one
- Another experiment—you get some choice of which one. (but I reserve the
right to assign)
- Final experiment—you get some choice of your experiments (but I reserve
the right to assign).
- Peer editing and re-writing the lab reports
- Oral presentations
Groups
I may allow you to work in groups of up to three. In no
case will you work with any specific individual on more than two of your
experiments. I reserve the right to restrict your choice of partners, and I may
even encourage or require you to work alone.
Absences and Tardiness
On the occasions we have formal classroom
time you are responsible for the material presented. Contact a classmate for
the notes.
Preparing to do an Experiment
There are several
steps to take before you actually do an experiment.
- Come up with an experiment
- Gather more information, especially get a good grasp of the underlying
physics.
- Familiarize yourself with the equipment
- Look for more information in your text books or elsewhere
- Talk with me before finalizing your choice
- Study the experiment
- Map out a strategy
- Locate necessary equipment
- Convince me you know what you are about to do
Lab Notebooks
You will maintain a notebook
of your lab experience. It is an up to date diary of your lab work. It should
contain dates, names, times, equipment lists, diagrams, raw data, musings,
ideas, sketches, casual observations... One good model is to write only on the
right hand page, and use the left hand page to insert graphs and tables or other
computer-generated information. They may be taped or glued in place. In very
formal cases one would sign and date across the boundary of such inserted items.
The lab notebook is the basis for your lab report, which should contain nothing
that isn't in the notebook, at least rudimentarily. It should be decipherable
by your colleagues, but is intended to be a working document, not a finished
product. I will examine these notebooks from time to time without notice.
Should any of you prefer to do some online, electronic sort of lab notebook,
I am quite willing to let you do so. This is the 21st century, and many research
organizations do it electronically. I must have access though.
Here are some guidelines:
- One or two blank pages for a table of contents
- Number the pages
- Never tear out pages
- Date the entries
- Write only in ink
- Put in clear titles for each experiment
- Clearly state the goal and motivation of the experiment
- Equipment list, and source, especially if you borrowed it
- Errors may be crossed out, but should still be legible
- No blank pages or large blank spaces, although you may choose to write on
only one side of the page, but be consistent.
- Include relevant equations that you connect to your experiment
- Sketches are good, but make them schematic, not artsy
- Develop the mathematics of your experiment—Derivations which start with
fundamental physics are appropriate
- Clearly indicate data processing and statistical methods used
- At some point you should have a clear, concise outline of your
procedure
- Tell the reader what you did and why you did it
- Address problems and their resolution
- File name and location of computer files relevant to the experiment
- Computer printed figures and tables may be taped in.
- Speculation is good—make notes to yourself of things to try
- Clearly state the result
- Error analysis
- Proper attribution for external sources of information
The written products in this class are intended to help you learn to do
professional, journal style articles. Communications to the professional
community via journals are very different from other written products, for
example, a "lab report" in most other lab classes has a very different audience
and intention than the articles you write in this class. Similarly for a final
grant report or final project report to a funding agency. Each has its purpose
and audience, and are consequently very different from one another. It is vital
that you understand the purpose, audience, format, and editorial standards for
any written product.
Each student will produce and submit their own report, even though you may do
the experiment as a group. While you may work closely together on the
experiment, each student writes up their own report, in the appropriate format
(i.e., using the LaTeX template suitable to their profession), and each student
should be completely competent in the details of data manipulation and analysis.
Reports are expected to meet the highest editorial and scientific standards.
Pretend it is being submitted to a refereed journal for publication and that
your job is on the line. The details of your format are dictated by those used
in a journal you choose which is consistent with your career goals. The term
"lab report" is somewhat of a misnomer, as you turn in a lab notebook, and your
formal write-up is more of a journal submission format.
These formal reports are the focal point of your work. The experiment isn't
worth doing unless its results are communicated to others. A generic,
everything is OK, no significant errors, good layout, adequately conducted,
reasonable conclusion lab will get you "B". Subtlety, insight, and cleverness
can get you more. Lab reports are written up individually, even though
experiments may be conducted as a group. It is inappropriate (i.e., it is
considered academic dishonesty) to pass lab reports down to students in future
classes, or to get them from previous classes.
The editorial guidelines used by the American Physical Society or American
Astronomical Society will generally be followed unless you convince me that you
should follow the guidelines of another organization. If your career goals and
academic path are consistent with your case it will likely be fine with me.
See example papers in journals such as Physical Review, or check out their
online style
guide, or the Astrophysics style
guide
Reports will ordinarily contain
- An abstract of no more than 100 words. A concise summary of your
experiment and the results.
- A brief introduction clearly stating the physical principles involved and
the goal of the experiment.
- Background and references, historical and/or scientific (Do not make this
extensive).
- Clear description of the procedures and a schematic illustration of the
experimental setup.
- Relevant data, graphical and/or tabular. Do not include extensive raw
data.
- Description of the analysis of the data, the result, the uncertainty, and
comparisons with generally accepted results
- Conclusions: what can you say based on your experiment? How does your
result relate to the goal of the experiment? Is the theory upheld by the
experiment? Do not make this a personal commentary on the experience you had
doing the lab.
- Suitable primary references.
- An appendix with a summary of your statistical methods and tools
- An appendix with a summary of your computational methods and tools (that
are not statistical in nature).
The Checklist— Pitfalls, Tips, and Hints...
- Abstract: comprehensive, informative, and includes the answer. No
references in the abstract.
- Ask yourself: "What is the purpose of this section?" "What is the purpose
of this paragraph?" "What is the purpose of this sentence?"
- The report should be written at the appropriate technical level—for your
peers.
- Keep in contact with me during the experiment. Brainstorm with me. The
more you tell me what you are doing the more likely I can save you some
time.
- Tables and figures are usually best placed as soon as feasible after they
are referred to in the text. Note that LaTeX has its own way of deciding
where to put them, but you do have some influence over it.
- Start the write-up early in the experiment. It will help you decide what
data you need, and may suggest extra experimenting.
- The word "then" is often misused/overused.
- Lead in to equations properly. Look in books and technical papers to see
how one leads into an equation. Also, you must define all variables when they
first appear.
- Use superscripts, subscripts and other typography appropriately.
- Use symbols, abbreviations, and language that are consistent with your
professional identity.
- Include an answer and uncertainty, with appropriate significant figures,
and units.
- When possible, compare your result with accepted results, and give a
reference
- Appropriate significant figures
- It is probably best to write in the past tense.
- Figures—Keep them simple, make them schematic rather than artistic.
They should be numbered and include a useful caption. They connect variables
in the setup to variables in the math.
- Graphs—Should be simple, but complete, with axes labeled, and data
points, and fitted functions distinct from one another. A figure should be
numbered and include a descriptive caption.
Things NOT to
include
- Do not include details we don't care about, e.g., "...we tried... but it
didn't work...", the reader generally doesn't care about things that didn't
contribute to the answer, or trivial details about instruments such as "We
used detector number 3," or obvious things such as, "we turned the instrument
on... we recorded the data..."
- Don't use contractions.
- Avoid "cute" words, i.e., ones you feel should be enclosed in quotes.
- Do not make subjective statements such as "our results are good." Be
objective, and let the reader judge you.
- Do not give a list of materials/equipment/procedural steps.
In addition to the guidelines above, the following will be considered when
assigning a grade to your report.
- Difficulty of the experiment
- Thoroughness of the experiment
- Creativity and originality
- Timeliness of your assault on the experiment
- Professionalism—care of equipment, clean up...
- Your level of effort
You will make oral presentations in several ways. On occasion you will be
asked to give a 1-2 minute status report on your current experiment. This will
likely be without notice. Finally, you will give a seven minute formal
presentation, probably, but not necessarily, on your third experiment.
The formal presentation will be given during a final exam period for our
class. The talks follow a standard presentation format used at scientific
meetings. The talks will be seven minutes long (+/- 1 min), and use suitable,
professional-quality visual aids. For a really good primer, see the MIT
Sample. Another good set of tips for scientific
talks.
Talk Details
- 7 minutes long, penalties for outside 6-8 minutes.
- Slides should be done using LaTeX or PowerPoint. I will give you a LaTeX
Beamer template that is easy to adapt. LaTeX
Beamer, another
Beamer page, or LaTeX PowerDot,
which I haven't used, but you may.
- Make text large and easily readable
- Don't have a lot of dense text
- Do use diagrams, graphs, and charts
- Talk to the audience. Do not read to them
- Have it visually appealing, but not distractingly so
- Make certain that everything is viewable by the audience. Note that some
colors or color combinations don't work well with room-scale video
projectors.
- Circuits and measurements proficiency exercise due Friday, 9 September,
5:00 pm.
- LaTeX-based Proficiency Exercise are due Monday, 12 September, 2:00pm.
Email pdf to me.
- e/m ratio formal written report due 2:00 pm, Monday, 26 September.
- Bring three copies, two that are anonymous (no names). Peer editing in
class that day.
- Re-writes due Monday, 3 October, 2:00 pm. One copy, as a pdf email
attachment to me.
- Second experiment is due 2:00 pm, Monday, 24 October. Bring three copies,
or, email the pdf to me by noon and I'll print it. Peer editing in class that
day.
- Re-writes due – a week later 2:00 pm, as a pdf email attachment to
me.
- (revised post-huricane) Oral presentations Exp 3
– You will present Monday, 12 December 1 pm — (Location TBD).
- Experiment 3 write-up is due – noon, Thursday, 15 December as an email
attachment pdf to me, make sure I acknowledge receipt. The lab notebook needs
to get to me in physical form somehow by noon the same day. Of course earlier
is fine too.
The due dates above for things up to an including experiment 2 are subject
to change a little, but there will be suitable notice. Late assignments may be
accepted (at my whim), but will ordinarily be penalized, more so each day they
are late. It is especially important that you turn in the first write-ups on
time so you can benefit from peer editing.
Grades
The accumulation of grades is as
follows. We do three experiments. For experiments one and two you submit an
original lab report, then we do some editing, and you submit a revised version.
The original and its revision are each graded, and carry the same weight. The
third experiment is a one-shot effort—no revision. In the overall grading
scheme the first experiment carries a weight of 2, the second a weight of 4, and
the third a weight of 6.
I assign letter grades to papers, lab notebooks, and talks. The letter grade
is assigned a number as in the College's grading scheme (A=4.0, A- = 3.7...).
Proficiency exercises and quizzes are graded on a 10-point scale, which is
rescaled to a 4.0 scale by dividing by 2.5. The weighted average is calculated
to determine the final grade. Below are the relative weights of the pieces of
your semester grade.
Lab reports |
70% |
Lab Notebook |
5% |
Quizzes and proficiency exercises |
15% |
Oral Presentation |
10% |
Total |
100% of course grade |
Disposal of
submitted work
I will dispose of old, unclaimed reports, lab notebooks,
and other submitted materials about a month into the next semester, so if you
want them, please contact me before then.
Other Information
Textbook: None
Course Pre/Co-requisites:
phys230, or phys225 or permission
Learning Objectives —
This course
endeavors to aid the motivated student in the following tasks:
- Preparing an article, based on experiment, that adheres to basic
scientific writing standards.
- Learning the elements of experiment design
- Learning the use, operation and limitations of experimental equipment
- Identify experimental limitations
- Learning to be a critical observer.
- Learning to analyze statistical aspects of experimental physics.
- Draw valid conclusions from your results
- Preparing a scientific talk, based on experiment, that adheres to
professional presentation standards.
- Learning the professional standards associated with doing ethical work in
the physical sciences.
Learning Outcomes —
At the end of this
course, successful students will be able to:
- Define and produce a model of a physical system
- Create a model of the measurement system
- Analyze measurement data
- Produce effective graphical summaries of data and results
- Design the experiment and apparatus
- Identify problem issues and design troubleshooting strategies using the
principles of physics
- Apply computational tools to analysis of data
- Select and use appropriate test and measurement equipment
- Construct and deliver effective oral and written communications in a
professional manner
- Analyze, identify and quantify uncertainties and errors using statistical
methods
- Assess and defend conclusions based on your experiment
Accommodations for Students with Disabilities —
Any student eligible for and
needing accommodations because of a disability is requested to contact me as
soon as practical or as soon as you have been approved for services so that
reasonable accommodations can be arranged. I'm easy to get along with.
Academic Integrity —
It is expected that you will adhere to the university's
honor code and student code of conduct, as can be found in your official CofC
student handbook.
16 Oct 2016