Rubber Band Lab

Highlights of the activity

1. This integrated laboratory activity is designed to help students appreciate how Maxwell relations can be applied.
2. Students measure the tension in a rubber band as a function of both temperature and length.
3. In the lab write-up, students analyze their data using a Maxwell relation, the First Law, and the definition of work to find the change in internal energy, entropy and free energy for an isothermal stretch.

Reasons to spend class time on the activity

This lab provides an introduction to the process of making macroscopic measurements, with following analysis demonstrating some of the power of thermodynamics. It also demonstrates the negative thermal expansiveness of rubber, which is the principle prediction of the “entropic spring” statistical model.

Reflections

• Reflections from the original implementation.

• Reflections from "official" adapters/adopters.

• Reflections from the general public.

Instructor's Guide

• Wiki version

Student Handouts

eerubberbandhand.pdf

eerubberbandhand.tex