Oxygen
5 Minutes
Oxygen for kids: discover how oxygen was found, its unique properties, and its role in combustion, rusting, and rockets. An English science lesson.
- How Scheele discovered fire air and Lavoisier named oxygen
- A candle experiment showing oxygen is needed for combustion
- How oxygen causes iron to rust and fuels rockets in space
What this lesson teaches
Oxygen is a chemical element that exists in the atmosphere as a gas made of two bonded oxygen atoms, playing a vital role in burning and forming compounds across nature.
Discovery and abundance
- In 1772, a Swedish chemist and pharmacist named Carl Wilhelm Scheele burned mercury oxide, collected the gas released, and named it fire air because it supported combustion.
- A French chemist named Antoine Lavoisier later gave this element the name oxygen.
- It is the most abundant element on Earth after nitrogen, and the third most abundant element in the universe after hydrogen and helium.
- Trees, plants, and creepers release oxygen gas through photosynthesis, while oxygen also binds into compounds like water with hydrogen and soil with silicon.
Physical and chemical properties
Every chemical element has physical properties, such as appearance, color, melting point, and boiling point, alongside chemical properties that determine how it reacts with other elements. The physical properties of oxygen include being completely odorless, colorless, and a poor conductor of heat and electricity. Chemically, oxygen reacts with both non-metals and metals, such as slowly reacting with iron surfaces to produce a reddish coating called iron oxide, or rust.
Oxygen in combustion
- Combustion is the chemical reaction where a substance burns in the presence of oxygen.
- A burning candle combines carbon with atmospheric oxygen to release carbon dioxide, but the flame dies if covered by a jar once the trapped oxygen runs out.
- Striking a matchstick causes its red phosphorus coating to react with oxygen, transforming into white phosphorus before igniting into a flame.
- Hydrocarbon fuels such as the propane gas used in kitchen stoves contain only carbon and hydrogen, and they cannot burn without oxygen.
Uses in metalwork and rocketry
Oxygen is widely used in metalworking when mixed with acetylene gas, producing an intense flame that can melt, cut, and weld metal pieces together. It is also essential for space travel, where rocket engines must operate outside the atmosphere. Because space contains no natural oxygen, rockets carry tanks of liquid oxygen as an oxidizer. Mixing this liquid oxidizer with the rocket fuel allows combustion to happen, generating the power needed to propel the vehicle forward.