• Question: How are come you are upside down when you look at one side of a spoon and it’s the opposite on the other side?

    Asked by 876heam32 to Eoin, Fiona, Ivor, Karl, Pattie on 5 Mar 2018.
    • Photo: Eoin McEvoy

      Eoin McEvoy answered on 5 Mar 2018:

      This is a little tricky to explain, but has to do with how the light bounces back off the shape of the spoon. When our eyes see an image on the spoon, this is because light has been reflected off it.

      Let’s start easy – when we look in a mirror, light gets reflected back to our eyes in a straight line, so we see a perfect image of ourselves. Like if you throw a ball against a wall it will come straight back.

      Each side of the spoon is like a curved mirror. On the back of the spoon, light reflecting off the top will be angled upwards when it bounces back, and light reflecting off the bottom will be angled down. When our eyes sense all this light it looks like the image on the spoon has been stretched.

      On the front of the spoon, the mirror curves inwards. Now light bouncing off the top part gets reflected downwards, and light bouncing off the bottom gets reflected upwards (so when bounced back its like the light (particles) have swapped places). When our eyes detect all these pieces (particles) of light, the image ends up upside down.

    • Photo: Fiona Freeman

      Fiona Freeman answered on 5 Mar 2018:

      A spoon is also a concave mirror. When you look at yourself in a normal mirror light comes in and gets reflected, and that’s how you are able to see your reflection. But when you look into a concave mirror (a mirror that bulges inwards like a spoon) two things can happen from up really close you look bigger and right way up. However when you look further away you look smaller and upside down. This is all how the light bounces off the spoon. It’s a fun experiment to try.

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