We are teaching on the Law of Conservation of Energy. Fire is a great discussion starter because it is so visual. We use demos like this to talk about stored chemical energy being transformed into light, heat, sound, and mechanical energy.
The evaporated alcohol fills the plastic container and it has a difficult time escaping when ignited. This rush to the exit provides the basic thrust for rocket engines. FYI: The children are at least 4m away and a new bottle is used each year.
