• Question: why is our blood red but our veins are blue?

    Asked by elliecone2000 to Jen on 20 Mar 2013. This question was also asked by mollie01.
    • Photo: Jen Todd Jones

      Jen Todd Jones answered on 20 Mar 2013:

      Hi Ellie

      Our blood appears blue in our veins but this is actually the colour of the walls of the veins, the blood inside is pretty much colourless actually! Until it reaches the air if we cut ourselves, the oxygen in the air mixes with the blood and makes it appear red – as it would inside the body when the oxygen from the lungs is passed to the blood in the arteries but not the veins.

      Hope this answers your question 🙂 we once had this as a pop quiz question in primary school, I’ve never forgot the answer, we spent half an hour trying to guess the colour of blood in the veins and couldn’t believe it wasn’t blue!

      Jen

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