See also: Combustion
Explosions are rapid reactions or physical events that release large amounts of energy in a very short time. This category explores the scientific principles that explain why they happen and what factors contribute to their intensity. Studying explosions provides a dramatic context for understanding energy release and gas behaviour.
| Demonstration | Materials | Difficulty | Safety | Summary |
|---|---|---|---|---|
| Cannon Fire Reaction | ★★☆ | ★★☆ | ★★★ | Hydrogen peroxide reacts with potassium permanganate to generate bursts of oxygen that make a burning ethanol mixture crack, pop, and roar like cannon fire; adding a metal salt can color the flame. |
| Hydrogen Balloon Explosion | ★★★ | ★★☆ | ★★★ | A helium-filled balloon and a hydrogen-filled balloon are ignited to compare their reactions. The helium balloon produces no reaction, while the hydrogen balloon explodes with a loud sound and flame, illustrating combustion and the differences in gas properties. |
| Hydrogen Mini Rocket | ★★☆ | ★★☆ | ★★★ | Hydrogen and oxygen gases are produced in the lab through chemical reactions, then combined and ignited to propel a small rocket across the room. The demonstration highlights multiple types of chemical reactions: double replacement, decomposition, combustion, and synthesis. |
| Hydrogen and Oxygen Exploding Bubbles | ★★☆ | ★★☆ | ★★★ | Electrolysis of dilute sulfuric acid produces hydrogen and oxygen gases, which are collected as soap bubbles. When ignited, the bubbles explode with a loud “crack,” demonstrating electrolysis, gas recombination, and energy changes. |
| Lycopodium Powder Fireball | ★★☆ | ★★☆ | ★★★ | Lycopodium powder, when ignited in a pile, burns slowly due to limited oxygen contact. When dispersed as a fine dust cloud and ignited, the vastly increased surface area causes rapid combustion, producing a dramatic fireball or small explosion. |
| Sodium in Water Explosion | ★★★ | ★★★ | ★★★ | A large chunk of sodium metal is added to a plastic bowl of water, it catches fire the explodes. |
| Whoosh Bottle | ★★☆ | ★★☆ | ★★★ | A small amount of alcohol is vaporized inside a large plastic jug and ignited at the opening, producing a dramatic “whoosh” sound and a burst of blue flame. |
Materials
★☆☆ Easy to get from supermarket or hardware store
★★☆ Available in most school laboratories or specialist stores
★★★ Requires materials not commonly found in school laboratories
Difficulty
★☆☆ Can be easily done by most teenagers
★★☆ Available in most school laboratories or specialist stores
★★★ Requires a more experienced teacher
Safety
★☆☆ Minimal safety procedures required
★★☆ Some safety precautions required to perform safely
★★★ Only to be attempted with adequate safety procedures and trained staff