• Question: Why does blood turn red when it touches oxygen?

    Asked by BladeFight to Stephen, Saoirse, Dervil, Moises, Pramod on 7 Nov 2016. This question was also asked by 476ghtg26.
    • Photo: Dervil Cody

      Dervil Cody answered on 7 Nov 2016:

      Actually, blood is always red, even when it’s inside the body. When you are cut, and the blood is exposed to the air, it reacts with oxygen and turns a brighter shade of red. This reaction happens because Hemoglobin in the blood contains iron, and when it reacts with oxygen in the air, it forms iron oxide. Iron oxide is the same material which makes up rust, which as you know also has a reddish colour.

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