The egg start to decompose and produces gas. Some of that gas escapes through the shell, so the egg’s mass decreases, which causes the density of the egg vs water to drop.
As an egg gets older it starts to break down, so it’s density becomes less. Eventually it’s density will be less than the water so it’ll begin to float.
Why is this though? What’s the science for making old eggs float?
The egg start to decompose and produces gas. Some of that gas escapes through the shell, so the egg’s mass decreases, which causes the density of the egg vs water to drop.
https://www.thoughtco.com/why-rotten-eggs-float-4116957
Thanks for this explanation! I couldn’t understand how the overall mass of the egg would change, even if some of the contents turned to a gas.
As an egg gets older it starts to break down, so it’s density becomes less. Eventually it’s density will be less than the water so it’ll begin to float.