• Question: do you think it is possible to bend light?

    Asked by 07creagand to Alastair, Emma, Hywel, Keith, Vicki on 21 Jun 2010 in Categories: .
    • Photo: Keith Brain

      Keith Brain answered on 21 Jun 2010:

      Yes! Here are some ways:

      – Light will bend whenever it hit a refractive index boundary at an angle. The “refractive index” is a measure of how fast light travels in a substance compared with that in a vacuum – so, air has a refractive index of close to 1, while glass has a refractive index more like 1.4-1.5. So, sending light through glass makes it bend – at school you might see this happen using a glass triangular prism (where you can also see a spectrum, or rainbow, of colours because different colours bend by different amounts). However, you can also see it irl – when you look at object in water (refractive index 1.3) it appears to be closer to the surface that it is.

      – You can gradually bend light by making materials that have different refractive indices in different places: this is used in many modern optical fibres, which are used for communications technology and high-end computing (or, rather, where computers might be in 5-10 years time) – a really hot area of technology.

      – Light bends around really heavy objects – light big black holes or stars. This is called “gravitational lensing” and was predicted by Einstein in his General Theory of Relativity.

    • Photo: Alastair Sloan

      Alastair Sloan answered on 21 Jun 2010:

      You can’t bend light as such. What can be thought of as bending light is called refraction and Keith has given you ways you can bend light

    • Photo: Vicki Stevenson

      Vicki Stevenson answered on 21 Jun 2010:

      light bends when it goes through different materials – try filling a bowl with water and dipping a wooden spoon in the water so part of the handle is still in the air – the spoon will look bent. That’s because the water has bent the light!

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