Why do rotten eggs float in water?
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My mom told me, that to check whether an egg is rotten, sink it in a glass of water, and if it floats then it is rotten. I didn't find any explanation for this phenomenon. If anyone knows please answer.
The domestic chicken's egg shell has about 7000 pores that allow the embryo to breathe. When an egg rots the yolk and surrounding materials decompose and they give off gasses which can pass through the shell. This allows mass to leave the interior of the egg resulting in less density for the volume of the egg making it more buoyant.
It doesn't need to be rotten. When the egg is getting old, it evaporate water and looses mass while drying. Even if not rotten.
