A follow up question to this eggceedingly good one Why do rotten eggs float in water?
There are already some good methods here
https://www.wikihow.com/Tell-If-Eggs-Are-Raw-or-Hard-Boiled
It's clear enough why most of the methods work but...
In 'other tests' number 3, a torch is shone through the egg, but why does the boiled egg not allow as much light through as the liquid egg?
The methods in the link you give are good.
In 'other tests' number 3, a torch is shone through the egg, but why does the boiled egg not allow as much light through as the liquid egg?
Have you never cracked a raw egg? The uncooked white is not white, it is a colorless jelly. When you shine a light through, it is only the yolk that will stop diffusion. If it is boiled, hard or soft, the white has coagulated and light does not go through.
