Why does a glowing splint relight in oxygen?

A glowing splint relights in oxygen because oxygen supports combustion, providing the necessary conditions for fire to reignite.

When a glowing splint is introduced into a test tube containing oxygen, it relights. This is because oxygen is a supporter of combustion. Combustion is a chemical reaction that produces heat and light. This reaction typically involves a substance (in this case, the splint) reacting with oxygen.

The glowing splint test is a simple yet effective way to demonstrate the presence of oxygen. When a splint is lit and then blown out, it continues to glow. If this glowing splint is then placed into a test tube containing oxygen, it will relight. This is because the oxygen in the test tube provides the necessary conditions for the splint to reignite.

Oxygen is a key component in the fire triangle, which is a model for understanding the necessary ingredients for most fires. The triangle illustrates that fire needs three things to exist: heat, fuel, and an oxidising agent (usually oxygen). The glowing splint provides the heat and the fuel, while the oxygen in the test tube acts as the oxidising agent.

When the glowing splint, which is already hot and has the potential to catch fire, is introduced into the oxygen-rich environment, it relights. This is because the oxygen allows the combustion reaction to continue, reigniting the splint. This reaction continues until either the fuel (the splint) is used up, or the oxygen supply is cut off.

In summary, a glowing splint relights in oxygen because oxygen supports combustion. The oxygen provides the necessary conditions for the splint to reignite, demonstrating the role of oxygen in the fire triangle.