Mechanics: Bologna Bottle

PIRA Class: 1R20.60

Purpose:
To demonstrate how the stress distribution within an object can result in unusual strength and fragility characteristics.

Description:
When it is made, the glass bottle is cooled rapidly resulting in large internal strain. The outside of the glass is then reheated and allowed to cool slowly removing the strain. The result is a bottle with an extremely tough outside but very fragile inside. The outside can be used to hammer a nail while dropping a small rough shard inside the bottle can cause it to break.

We have a box of small Bologna bottles. When a bottle is held between crossed polarizers you can observe the stress in the glass. The stressed glass rotates the angle of polarization and the amount of rotation is wavelength dependent resulting in different colors in different locations.

Equipment:

Bologna bottle, two larger polarizers

Location:

Shelf 362 (polarizers)

Videos
Video demonstration