Bologna Bottles - Physics Demonstrations - Bologna Bottles | Physics Undergraduate Labs

When the bottle shatters, glass fragments explode with considerable force in all directions. Always contain the bottle in a clear plastic box or wrap it in heavy cloth. Require safety glasses for the demonstrator and front-row students. The explosion releases stored elastic energy equivalent to several joules.

Purpose

Bologna bottles withstand hammer blows but shatter instantly when a small carborundum particle is dropped inside. Students see how rapid cooling creates compressive surface stress that resists impact, yet a tiny scratch reaching the tensile interior releases stored elastic energy catastrophically.

Clear glass Bologna bottle with thick rounded bulb and narrow neck, resting on dark surface

Figure 1:

Safety Warnings

Warning: Flying Glass Hazard

Purpose