6H35.50 Stressed Plastic Between Polaroids
Plastic objects between crossed polarizers produce colour variations in the plastic, which are caused by stress-induced birefringence. There is a set of plastic pincers to show the effect of stress on the plastic.
-  Polaroid sheet
-  Plastic French curve
-  Plastic pincer
-  Overhead projector
- Turn off the lights.
- Turn on the projector.
- Put the French curve and pincer on the projector as a control experiment.
- Place the French curve between the crossed polarizers on the projector.
- Place the plastic pincer between the crossed polarizers.
- Pinch and unpinch the pincer.
- PIRA 6H35.50
- Don't attempt this at home!
If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.