Boiling Eggs Turning Solid
Date: June 2006
Why is it that when you boil an egg, it turns hard?
What properties does it have that make it do so?
Eggs are largely protein, and protein molecules tend to be
long and folded up on themselves. Heating an egg, causes the
protein molecules to unfold and link together with other
protein molecules. Very large chains of many protein
molecules result. The joining together of the individual
protein molecules, into much larger ones, results in the egg
becoming more solid. Other common substances such as plastics
and rubber are made a similar way by causing smaller
molecules that start off as liquids or even gases, to join
together into large interconnected chains, resulting in solid
or rubbery substances.
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Update: June 2012