• Question: When clothes are wet why do they turn black

    Asked by 499etrc to Daniel, Freya, James, Miranda, Usman on 18 Jun 2015.
    • Photo: Usman Bashir

      Usman Bashir answered on 18 Jun 2015:

      Well we see cloth as dark or bright based on how much light they are reflecting. If they reflect a lot of light, they appear bright, and if they reflect less, they appewar dark.

      When wet, a lot of light that strikes the cloth gets scattered due to tiny water molecules. so they only reflect a small amount back to us. Therfore, they appear dark until they get dry again. Hope that makes some sense 🙂

    • Photo: Freya Wilson

      Freya Wilson answered on 18 Jun 2015:

      Good question! We see colours because a mixture of different colours of light reflects off a surface. If all the colours are reflected and reach our eyes then we see white light. If none of the colours are reflected and all are absorbed then we see black.

      If only blue light is reflected (and all other colours absorbed) then we see blue, and if only red light is reflected (and all the rest absorbed) then we see red.

      So, if something is wet and it looks dark that means that the water must be absorbing lots of the light

    • Photo: Daniel Hewson

      Daniel Hewson answered on 22 Jun 2015:

      Great question! Really had to think about this. Clothes do get darker when wet and the explanation is best understood when a white t-shirt is considered. A dry white t-shirt quite happily scatters light so that all we see is the t-shirt fabric surface. When water is added to the fabric the t-shirt appears translucent which means that the water guides the light through the fabric and back out again revealing what is under the t-shirt. The thicker and darker the colour of the fabric the more it will absorb the light being guided through by the water.

    • Photo: Miranda Jackson

      Miranda Jackson answered on 22 Jun 2015:

      I agree with the other scientists. The colour we see is due to the path the light takes when it encounters an object. Water allows light to pass through fabric more easily, so less of the light is reflected into our eyes, making the fabric appear darker.

    • Photo: James Gilbert

      James Gilbert answered on 26 Jun 2015:

      Not much I can add to this one!

      The water reduces the reflectance of the material, bouncing less light back and so it appears darker!

      ( Sorry I missed this question last week 🙁 )

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