• Question: why dont we see in the dark?

    Asked by anon-37831 to Hannah, Ian, Jono, Mark on 26 Jun 2013.
    • Photo: Hannah Brotherton

      Hannah Brotherton answered on 26 Jun 2013:

      Hi 10cargeoa,
      We can see because of things called rods and cones in our eyes. The rods have a molecule called rhodopsin which changes shape when light comes into contact with it.

      Rhodopsin is the chemical that allows night-vision, and is extremely sensitive to light.
      When light hits it, it bleaches and needs about 30minutes to work again. This is why if you put on a light at night and switch it off really quickly we can’t see a thing. but after a while our rhodopsin regenerates and we can see a bit better in the dark.

      Why we can’t see that well??? this is because our eyes need light to see. Light carries information about what we see, without it, our brain doesn’t have any information about what we are looking at.

      I have terrible vision at night …..and I ate lots of carrots when I was younger lol

    • Photo: Mark Hodson

      Mark Hodson answered on 26 Jun 2013:

      Hi 10cargeoa,

      because we need light to see by. Some animals can see using infra-red light rather than visibile light so when it appears dark to us

      cheers

      m

    • Photo: Ian Wilson

      Ian Wilson answered on 26 Jun 2013:

      Hi 10cargeoa,

      Our eyes work by catching light – they’re kind of like a funnel for it. Imagine you’ve got a funnel and you fill in with water. The can be loads of water in there but it will all be redirected to the middle to flow down the neck of the funnel. Our eyes do the same thing with light – as light hits them, it’s bent towards the back of the eye.

      At the back of the eye there are cells called rods and cones. These collect light and, together, they recognise colours and shades. This information is then passed onto our brain, which makes sense of what we see.

      If we’re in the dark, there’s no light for our rods and cones to pick up. That means there can be no signals sent to our brain, so we don’t see anything. But, have you noticed that just the smallest bit of light is enough to let us see something eventually? Our eyes are VERY sensitive 🙂

      Ian

    • Photo: Jono Bone

      Jono Bone answered on 27 Jun 2013:

      Hi 10cargeoa,

      You see objects by the light they emit or reflect. In the dark there is not much light to reflect from and object so you cannot see it. Some animals like cats and owls can see better in the dark because the pupils of their eyes can open wider and receive more light than our eyes can.

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