Science
What is Oxidation?
Oxidation is a chemical reaction in which a substance loses electrons — often by combining with oxygen. Rusting iron, a browning apple, and burning fuel are all oxidation, and it is always paired with 'reduction,' where another substance gains those electrons.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains oxidation.
Key things to understand
- 1At its core, oxidation is the loss of electrons by an atom or molecule.
- 2It often involves oxygen, as in rust, fire, and respiration.
- 3It always pairs with reduction (electron gain) — together called redox.
- 4It releases energy in burning and in your cells' use of food.
- 5Antioxidants are substances that slow unwanted oxidation.
Frequently asked questions
- Is oxidation always about oxygen?
- Not strictly — the modern definition is loss of electrons, but it's named after oxygen because oxygen so commonly causes it.
- What is a redox reaction?
- A paired reaction where one substance is oxidized (loses electrons) while another is reduced (gains them).
- What do antioxidants do?
- They donate electrons to neutralize reactive molecules, slowing harmful oxidation in food and in the body.