Physics 120/130 Laboratory
at Davidson College

Introduction to Experimental Methods

Structure of the Laboratory:

The introductory physics laboratory is a mixture of pre- and post-laboratory exercises, in-class experiments, computer simulations, and reports.  Laboratory sessions will usually be preceded with class discussion or demonstration explaining specific procedures to be followed.  Laboratory exercises are designed to complement the theory presented in class and, as such, are often a compromise between the abstract world of point masses, frictionless tables, and massless strings usually assumed and the real world.  Hopefully the labs you will perform will "work" and give results in good agreement with the ideal.  We are trying to reinforce the abstract concepts of force, velocity, vectors, etc. with some real everyday phenomena in order to make the physics meaningful.  Often you will discover enough disagreement that you can make some intelligent observations as to the cause of the discrepancy; this is where you can and should add your ideas as to what caused the discrepancy, how you would improve the experiment, or how you would modify the theory to give better agreement.  These extras, together with how well the work is laid out, will vary from individual to individual, and will distinguish the good experimentalist.  During the first few weeks of lab you will be given instruction in the use of computers.  They allow the rapid analysis of more data than was possible previously and help reduce the time and tedium of such routine tasks as tabulating and graphing.  Computers have become a part of professional practice in the sciences and you need to be exposed to their use.  There are pitfalls, however, that will need to be overcome: bugs in programs or programmers and a general computer-phobia among the uninitiated.  With proper and careful operating procedures, a little work and understanding, and some occasional humor, these problems should go away.


For some laboratories the theory will have already been covered in class.  Pre-lab exercises will be assigned via the web the week before a lab, and they are to be done and submitted before you arrive at lab.  There will also be a few post-lab exercises in addition to the pre-labs and they are due before the next laboratory session.  You must read the lab before you arrive in lab and these pre-lab exercises are designed to test how well you are prepared for lab.


We will usually do the labs in pairs.  You should be sure that each student does a proportional amount of the work.  I reserve the right to ask lab questions on an exam. While you work together on the experiments, all of the analysis and writing should be done on your own.  Of course, you should verify that you are both getting the same answers.  Copying a lab or portion of a lab, even from your partner, is a violation of the honor code.

You will need a lab notebook, dedicated to the labs (I will collect it each week). A standard spiral bound, lined-paper notebook with pockets is required.

I will often give a lab lecture at the beginning of lab, usually lasting 15 minutes.  The lab write-up will be done in your notebook, and completed and handed in before you leave lab.  Expect to be in lab the full three hours each week. You may well be out early some weeks, but this can never be guaranteed and will certainly not always be the case.  Do not rush to get out early, as this will be reflected in your grade.

Labs will be graded on pre-lab/post-lab exercises, performance in lab, and lab write-ups.

The lab write-up should include (in this order):

Data and plots will usually be printed from the Excel spreadsheet and glued, stapled, or taped into your lab notebook.

If you prefer, you may do the lab write-up all electronically with Microsoft Word.


You may choose your own laboratory partners. Your choices will not be disallowed unless it becomes apparent that the partnership is lopsided, i.e., one person doing all the real work and the other acting as recording clerk. Remember you will be evaluated separately. The following laboratory listing is tentative and subject to change:

Copyright 2002 Wolfgang Christian and Mario Belloni.
Physlet problems are Copyright 2002 Wolfgang Christian and/or Mario Belloni . 
Physlets are a registered trademark of Wolfgang Christian.