• Question: Why are our veins blue and purple but our blood red?

    Asked by Sharmin_the BEST to Hayley, Jimi on 18 Mar 2016.
    • Photo: Jimi Wills

      Jimi Wills answered on 18 Mar 2016:

      Good question.

      The standard answer to this is that the blood in the veins has not oxygen, and that makes is blue. But actually, the blood is still red.

      The reason veins look blue is that they are much deeper in the body, and only blue light can penetrate that far in.

    • Photo: Hayley Moulding

      Hayley Moulding answered on 18 Mar 2016:

      Our blood and vessels are different colours. Our blood depending on whether it has oxygen in our not can be a different colour. Blood coming from our lungs where it has picked up oxygen will be red, whereas blood coming away from our body back to the lungs to pickup some oxygen looks more blue. It is because the blood is either lacking or has oxygen found to the centre of the blood cells. That is why it will look a different colour.

      The actual colours of the veins are to do with how deep the veins and arteries are in your body. It takes different lengths of light to be able to go further into our bodies to make them look that colour.

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