Og-2 Strain Polarisation
Published: Wednesday 15 March 2006 - Updated: Monday 28 March 2011
Aim
To demonstrate strain birefringence.
Apparatus
- Overhead projector
- Polaroid sheets
- Perspex models
- Strained glass
Diagrams
Click on pictures to enlarge.
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Strain Polarisation Pic |
Strain Polarisation Pics |
Description
The perspex models and the strained glass (caused by rapid cooling) are placed on the overhead projector with the polaroids in the crossed position. Strain present in the glass or induced in the perspex causes the object to become anisotropic and birefringent. This results in visible stress lines due to interference colours.