Fire that doesn’t burn you? How??

Equipment: glass container with water, liquid soap, flammable gas, lighter.

Some liquid soap is poured into a glass container with water. The solution is stirred. A flammable gas is passed through the solution. After dipping a hand in the solution, the experimenter collects some foam in the palm of the same hand and ignites it. The foam burns without burning the experimenter’s hand!

Reactions that absorb heat are called “endothermic reactions,” while reactions that release heat are referred to as “exothermic reactions.” For example, combustion is an exothermic process, which is why we feel heat emanating from fire. Meanwhile, water evaporating or ice melting are examples of endothermic processes. This experiment involves both types of reactions – when the flammable gas in the foam burns, a large amount of heat is released, which is immediately spent on evaporating the water covering the hand. As a result, the fire does not burn the hand!

Safe experiments await you in the MEL Chemistry subscription!

Safety precautions: Attention! All experiments are performed by professionals. Do not attempt.