Concepts

Birefringence

Overview

Calcite's birefringence produces two images of text with different polarizations. A correctly oriented polarizer screens out one of the images.

Details

Equipment

• [1] Calcite crystal
• [1] Overhead sheet with text
• [1] Polaroid sheet
• [1] Overhead projector

Important Notes

• The calcite crystal is fragile. Handle with care.
• The calcite crystal is an optical element. Please keep it clean by handling it with a tissue.

Script

1. Dim the room lights.
2. Turn on the overhead projector.
3. Put the sheet of text on the projector as a control experiment.
4. Put the calcite crystal over the text so that it duplicates the letters.
5. Rotate the polaroid sheet until you block one set of letters, then the other.
6. Turn off the projector.
7. Brighten the room lights.

Additional Resources