• Question: why do we get dizzy when we spin?

    Asked by adam777 to Hannah, Daniela, Ian, Jono, Mark on 23 Jun 2013. This question was also asked by bartra, maddypowpow.
    • Photo: Hannah Brotherton

      Hannah Brotherton answered on 23 Jun 2013:

      Hi adam777,
      We have little hairs in our ears, which move in a fluid. When we spin, the hairs and the fluid spin with us. But when we stop spinning, the hairs and water continue to spin, telling our brains that we are still spinning, even though we have stopped. This is why we get dizzy, because our body is telling us we are still, but our brain is telling us we are moving.

      Another example of differences in what our brain and body tells us is motion sickness or sea sickness

      When we are on a boat, our brain sees the ocean moving up and down, but we are not actually moving ourselves, we are just standing still on the boat. What our brain sees doesn’t match up with what our body feels. So the brain thinks we are sick or have eaten something poisonous, and is trying to make us sick to get rid of any toxins in our body. This is why some people shut their eyes when they are on a boat.

      😀

    • Photo: Mark Hodson

      Mark Hodson answered on 24 Jun 2013:

      adam777,

      Hannah has said it all – effectively the brain is getting two different and conflicting bits of information and it doesn’t like it!

      cheers

      m

    • Photo: Ian Wilson

      Ian Wilson answered on 24 Jun 2013:

      Hi adam777 and bartra,

      Your brain relies on your eyes and ears to understand it’s position and to keep balance. The problem with spinning lies in the ears.

      Your ears contain a liquid called ‘endolymph’, as well as nerve cells that are kind of like hairs, sticking out into the liquid. These hairs detect any movement in the liquid, which would be caused by your head moving. The hairs then send signals to your brain to say you’ve moved. The pattern and strength of the signals headed to the brain let it know how much your head’s moved.

      The problem is, when you spin, the liquid in your ears doesn’t move in the same way that your head does. Try putting some water in a wide glass and spinning it around. The water looks like its sticking higher up against the side of the glass, right? That’s because the force of the motion is keeping the water at the sides, so it doesn’t move in quite the same way as the glass.

      This is what happens to your body when you spin round. The liquid in your ears doesn’t quite keep up with the movement of your head. So, the hairs are sending signals to your brain saying your head is in one position, but actually, you’re head is now in another position.

      Meanwhile, your eyes are giving the brain accurate (if blurred) images, which contradict what the ear hairs are telling it. Your brain gets confused and can’t work out how to keep you balanced – should it believe the eyes or the ears?

      Hope that makes sense!

      Ian

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