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Q & A: Turning Brown

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Most recent answer: 10/22/2007
Q:
Why do things turn brown but not any other colours after being decomposed?
- PangJiingHuey (age 12)
Singapore
A:
Not being a biologist, I will give you a physics perspective.

Each compound is a certain color. If the petal of a flower is a vivid red color, for example, it is because the compounds present on the outside of that petal like to absorb all colors except for red. The same argument is true for blue, yellow, or any other color. If you take blue, red and yellow paint and mix it together, you get brown or black paint as a result. This is because the different compounds, when mixed together, will tend to absorb all colors of light, leaving little or no light to bounce back into your eye.

When something dies, many of the compounds that make it up will tend to get mixed together as it decomposes, and some of the compounds that made it up will decompose into new compounds that were not present before death. The result is that you often end up with a brownish or blackish color, just like when you mix lots of paint colors together.

Mats

(published on 10/22/2007)

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