My lab final exam is in mechanics. I use Matter & Interactions, so
students did "traditional" labs as well as VPython programming
exercises. I did not emphasize error analysis (though I think this is
really important!). During the labs, however, we did discuss good
measuring techniques. In a number of labs, students had to fit a curve
on a graph and use the resulting function.
I wrote my first draft of the lab last night. I'm giving the students a
"research" question and then grading them on the completeness of their
work. I define what I mean by completeness in the handout.
I wanted the research question to be simple, just as many of you
suggested, but one that would elicit what students learned in lab.
BTW This exercise is not only useful for assessing students' lab
skills, but it's also useful for assessing my teaching! I expect this
to be a difficult exercise for students.
Below is the research question and the rest of the handout.
----------------------------THE RESEARCH
QUESTION----------------------------
How is the change in the thermal energy of a bouncing ball during its
first bounce related to the initial height from which it is dropped if
it is released from rest?
------------------------------------------------------------------------
---------------------
LAB FINAL EXAM
Objectives
To demonstrate that you can apply fundamental physics principles to
“real” experimental questions and to
demonstrate that you have learned essential scientific skills, you
should be able to
• articulate a research question to be answered.
• design an experiment to help answer the question.
• set up and use appropriate measurement tools.
• conduct an experiment so that your conclusions are valid and
experimental error is minimized.
• analyze data using graphs; fit curves to the data; interpret the
best-fit function; use the resulting
function.
• use VPython to develop a model of the experiment; state the
simplifying assumptions of the model;
use numerical integration to apply the momentum principle and
definition of velocity to calculate
the momentum and position of interacting objects; graph and/or print
appropriate quantities; interpret
graphs.
• compare the predictions of your model to the results of your
experiment.
To be able to design and perform an experiment requires thinking skills
above and beyond simple rote
learning. I don’t expect this task to be easy, but I do expect you to
use previous lab activities to get ideas
about how to solve the problem. I also expect you to work together with
your lab partner. Two brains are
better than one, assuming that both brains are participating.
You will be given a single research question, and your “answer” to the
question will be graded on the
level of completeness. For example, a Grade-A response would probably
include:
Background : You should apply fundamental principles to the problem
showing how certain quantities are
calculated, what quantities should be measured, and what assumptions
are made. Pictures showing
the experiment are recommended. If an object is moving, you should
sketch the object at certain
positions and label things like its momentum vector, the net force on
the object (if known), etc.
Experiment Design : You should describe your experiment, how
measurements were collected, what measurements
were repeated, what calculations were made, what instruments were used,
what variables
were kept constant, etc. You should show attention to experimental
error and how the error was minimized.
Data analysis : You should graph your data, fit the curve, and
interpret the results–if a graph is appropriate
for analyzing the research question. Show any calculations useful for
answering the research question.
Simulation : You should write a VPython program to simulate the
phenomenon. Often, such a simulation
is a model that contains certain simplifying assumptions. You should
clearly state those assumptions.
Use your model to predict something and compare it to what you found in
your experiment. How does
the simulation compare to the experiment?