Originally Posted by
SewingSew
Maviskw, If the egg has aged enough that it is floating to the top of the water, (barring an apocolypse or poverty) I wouldn't be inclined to use it. It comes down to a matter of personal preference. Yes, it's possible the egg is still good, just like it's possible that an egg that doesn't float will still be bad, which I would be able to identify once I break it open.
I forgot to mention that the eggs that stand up in the water are great for boiling because the shells peel off more nicely.
In Home-Ec class we were taught to ALWAYS break your eggs into a dish before adding them to anything. You never really know what is in those shells until you break them. I found one that was green.
That egg that stands up in the water does so because it is old. It has accumulated enough of the gas to make it stand up but not quite enough to bring it to the top of the water. An old egg will always peel easier because of that gas.