What is oxygen?
Oxygen is a non-metal element that is a gas at room temperature. Its molecules contain two oxygen atoms.
Oxygen is vital for respiration, which is the process that transfers energy from glucose to cells.
Oxygen is necessary for burning to occur. However, burning will only happen when the mixture of fuel and oxygen is hot enough.
How is oxygen useful?
Oxygen is a non-metal element and is found naturally as a molecule. Each molecule is made up of two oxygen atoms that are strongly joined together. Oxygen has low melting and boiling points, so it is in a gas state at room temperature.
Vital for life
When animals breathe in, oxygen molecules enter the lungs and pass through the lung walls into the blood. The blood carries oxygen to the cells of the body, where it takes part in a chemical reaction with glucose. This chemical reaction is called respiration.
Respiration happens all the time in every living thing: it is how the cells receive energy. If an animal or plant does not have enough oxygen, it will not be able to respire and will die.
If the temperature is high enough, many substances will burn in oxygen. When a substance burns, it reacts with oxygen: this happens in wood fires and also in car engines, which burn petrol. The chemical reaction transfers energy in order to make the engine work. The scientific word for burning is combustion.