Moment of Inertia

Related Physics Education Research

None that I know of.

Overview of Worksheet

This laboratory experience was designed by my colleague Prof. Robert Simpson. This is an open-ended lab for which the students are asked to calculate the moment of inertia of a heavy pulley in two ways: using the definition and by experiment. They are given no other instructions than this; they are given the density of material (aluminum).

Professor Simpson is currently writing a laboratory text for publication. Interested parties can contact him via e-mail.

Approximate Time

Students need at least 4 hours to do this, over two class or lab periods. In the first lab they typically flounder quite a bit, but by the second class most of the students have a definite plan.

Required Student Background

This lab must come later in the semester when the students are familiar with the motion detector and MBL equipment. Also, students must be familiar with moment of inertia, torque, and angular acceleration. It may be valuable to announce that students will be given a pre-lab quiz that they must pass in order to do the lab. The pre-lab will insure that they have a basic understanding of the concepts involved.

Connections to the Tutorials

This compliments the tutorials on angular motion.

Required Equipment

A heavy pulley, weights, string, motion detector, MBL equipment. It is preferable to be able to tell the students that they can use any equipment that they think is necessary, and not put any equipment out on the table, as that gives more hints than necessary about how to solve the problem.

Evaluation of Worksheet

Anecdotal feedback: One student switched her major to physics because of this lab - it made her think!

We compared the performance of two groups - one group had the full two weeks to do the lab; the other group had only one week (due to short summer session) and was given more hints on how to do the problem. In the first group 20% (21/107) of students correctly answered a question about the tension in an Atwood machine, in the second group only 3% (1/29) got the correct answer. (Overall test averages were 79 and 80 respectively.)

Worksheet

because there are no detailed instructions for this lab, there is no worksheet to download.