How to find if and egg is not boiled before cracking it. If I have boiled several eggs and after that someone have mixed them with other not boiled eggs, how can I separate them. Of course I don't want to break the eggs.
What's with all those complicated answers? There's a very easy way to check, one that I always use when I don't know if an egg is boiled or not:
Simply put the egg on a flat surface and spin it fast. If it's boiled, it will continue spinning, otherwise it will stop in 1-2 seconds.
EDIT: As Peteris suggested in his comment, basically a boiled egg will behave as a solid object. So, try to spin your egg 5 full rotations in one push. If you can't make it, it's not boiled.
As a non cooked egg is fluid inside we can make use of the rotational energy stored there. Put an egg on your desk and rotate it fast (like a gyro). Then apruptly stop it with a finger, then release it again.
Case egg was cooked:
The egg will immediately stop spinning
Case egg was raw:
The fluid inside will continue rotation, hence making the egg start rotating again.
Option 1) Put the egg in water. A raw egg will have a tiny stream of air bubbles.
Option 2) Shine a strong flashlight through it. A raw egg will show light all the way through.
Option 3) Spin it on its end. The sloshy innards of a raw egg will cause it to wobble and a cooked egg will spin smoothly.