Lab 8 Materials - Quantitative Polarization
Self-Assessment Form
I hugely enjoyed this lab - preparing it, and watching you execute it. The teamwork both teams showed as you all worked beautifully together to get high-quality experimental results. It is clear that you all know and respect each other well enough to easily organize yourselves to complete a complex task. My hat is off to you all.
Julian sent me his team's data spreadsheet for sharing:
Team Julian Lab 8 Spreadsheet
Here is what the data looks like (blue squares) compared to a cos^2 law with a phase shift and amplitude that best "fits by eye" (red line).
The data clearly validates the model, Malus' law to within a few percent. A detailed study of this experimental dataset could be done to determine the degree to which the cos^2 law matches the data, perhaps someone will undertake this quantitative task. Also instructive would be a plot showing the uncorrected-for-drifts readings vs angle and the cos^2 law. Since the input beam intensity varied by 40%, the comparison would be graphic in showing the value of performing a chopping experiment. Instrumental drifts are invariably present at some level in every experiment. An experiment seeking the best possible sensitivity must take these drifts into account.
Above is a snapshot of the 2 polarizers with their mounts "blocked" using 1/4-20 bolts in the table to achieve a relatively repeatable position. This technique facilitates rapidly moving each polarizer out of the beam and back in at will without having to fuss much about obtaining correct placement. Just push it (gently) up against the blocking bolts.
Team John emailed me as well. Here is that team's data:
Team John Lab 8 Spreadsheet
