• Question: What is a reflection?

    Asked by The Ge Ni U S to Andrew, Jade, Jessica on 25 Jun 2015.
    • Photo: Jessica Wade

      Jessica Wade answered on 25 Jun 2015:


      Amazing question! It is all about light, and this year is the international year of light! We all know light travels in straight lines from the sun or another light source. We know this because we see shadows when light can’t get around an object. When light hits a shiny surface, the light rays bounce off. This is how we see things that aren’t sources- they bounce the light rays off and in to our eyes. Reflection is great on really flat lakes because we get a mirror image (flipped around) of what’s above the lake. It also tells us why we see a blue ocean- it reflects the sky! The sky is blue because of how air molecules scatter the sun’s light.

      If you have fibre optic internet, reflection also explains how that works! Inside the wires the beams of light are totally internally reflected, which means that none of their light leaks out the edge of the wire. Everytime a beam hits the wall of the wire, it is perfectly reflected and bounces to the next wall, where it is perfectly reflected again. It’s really efficient and doesn’t lose any energy, which is why fibre optic broadband is so expensive (but fast!)

    • Photo: Jade Owen

      Jade Owen answered on 25 Jun 2015:


      A reflection is where light waves bounce off a shiny surface. Our eyes then recieve the light and our brains process the electrical signals our eye recpters send to show you the image being reflected.

    • Photo: Andrew Fensham-Smith

      Andrew Fensham-Smith answered on 25 Jun 2015:


      Some materials absorb light, while not absorbing others. The light that something doesn’t absorb ‘reflects’. Imagine a ball and a sticky wall – you throw the ball and if the ball sticks to the wall, then you could imagine the wall has ‘absorbed’ the ball. If the ball bounces off, it’s been reflected. Almost everything around you reflects some light, which gives it it’s colour.

      But why do mirrors not have a colour? Why can you see yourself in a mirror but not on say, a white wall? Both reflect a lot of light on their surface. The difference is, that the mirror reflects light in the same direction, while the white wall scatters it around everywhere. Imagine the wall and ball scenario – except this time the wall is really bumpy. When you throw a ball at the wall, it bounces off in random directions because the wall is bumping it into a random direction. If the wall was completely smooth, you would be able to guess where the ball was going. In the smooth wall case – the angle the ball hits the wall, gives the angle the ball is reflected from the wall. A mirror is the same – the angle the light hits the mirror gives the angle it’s going to bounce off. Whereas when you have a white wall, the light is going all over the place, and your eyes can’t determine where the light came from before it hit the wall because it’s being scattered.

      Hope that makes sense!

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