Naked Science Forum

General Science => General Science => Topic started by: chris on 18/03/2016 19:18:42

Title: Why do wet things look darker?
Post by: chris on 18/03/2016 19:18:42

Water flicked onto a wall, paint that is not dry and freshly-washed hair are all darker than their dry equivalents. Why?

Title: Re: Why do wet things look darker?
Post by: guest39538 on 18/03/2016 21:28:43

Quote from: chris on 18/03/2016 19:18:42

Water flicked onto a wall, paint that is not dry and freshly-washed hair are all darker than their dry equivalents. Why?

Waters more reflective than the wall so the wall becomes a blacker body that can be seen through the transparency of the water?

In simple terms the water creates a barrier?

Title: Re: Why do wet things look darker?
Post by: RD on 18/03/2016 23:57:32

Quote from: chris on 18/03/2016 19:18:42

... freshly-washed hair ... darker than ... dry ...

Water-coated-fibres will be similar to fibre-optics ...
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fwww.thenakedscientists.com%2FHTML%2Fuploads%2F300x236xRTEmagicC_FibreOptics-stream_01.gif.gif.pagespeed.ic.7ZD73yi8wX.png&hash=d473d080bfa0895ebab78befa88b21a0)
http://www.thenakedscientists.com/HTML/experiments/exp/water-fibre-optics/

The internal-refection (https://en.wikipedia.org/wiki/Total_internal_reflection) will repeatedly redirect some of the light back towards the fibres where some will be lost as heat. These additional reflections from fibres, (losing some light-energy each time), would not have occurred if the fibres were dry.