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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.

  • 1
    For the future, you can mark your hard-boiled eggs with a sharpie before you keep them; that way you'll always know. – Justin Feb 19 '15 at 16:47
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    @Quincunx Are sharpies food-safe? Is there a food-safe permanent marking pen? Also you've got to prevent the person mixing the eggs from also marking the non-boiled ones. – Random832 Feb 19 '15 at 18:04
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    @Random832 Sharpies are not technically food safe, but, since you aren't eating the shell, it doesn't matter. The shell will protect the egg against any "toxins" that the sharpie could possibly introduce. – Nick2253 Feb 19 '15 at 23:13
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    Egg shells are very porous, especially after boiling, so I wouldn't recommend using anything toxic on them. – Mark Feb 20 '15 at 11:53
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    Visibly porous—if you ever colour eggs for easter, you’ll find that the colour dissipates through the shell. – Jonas Schäfer Feb 22 '15 at 13:07
53

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.

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    And if people are confused about "did it stop quickly or not", then the intuition is that a boiled egg behaves exactly in a way that you'd expect a solid object to behave and a raw egg, well, won't. – Peteris Feb 19 '15 at 19:44
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    Um this is precisely what "all those complicated answers" suggested, hours before you! – Lightness Races with Monica Feb 20 '15 at 2:19
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    @LightnessRacesinOrbit I'm looking at the most voted answer and it does start with rotation, but it's based on "abruptly stop[ping] it with a finger" which I think is unnecessary. Like suggested, a boiled egg will rotate as if it were solid, while a raw egg will stop very quickly (1, maximum 2 full rotations). – Bogdan Alexandru Feb 20 '15 at 8:53
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    Just a quick note: this only works with hard-boiled eggs. The question didn't specify whether the eggs were hard-boiled or soft-boiled. – The Spooniest Feb 20 '15 at 15:15
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    Alternately start the egg spinning, then very quickly stop it and let go. The boiled egg will stop, the raw one will start spinning again due to the fluid inside not stopping when you stop the shell. – Jon Story Feb 20 '15 at 16:23
64

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.

  1. Case egg was cooked:

    enter image description here

    The egg will immediately stop spinning

  2. Case egg was raw:

    enter image description here

    The fluid inside will continue rotation, hence making the egg start rotating again.

  • 1
    Abruptly stop it with a finger, then release it again, right? – Jasper Feb 19 '15 at 12:56
  • @Jasper: of course... my bad it all was there but only in my mind - thanks for this :) – Takkat Feb 19 '15 at 12:58
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    It works, but it could also spin right onto the floor if you're not careful. – Mooseman Feb 19 '15 at 13:05
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    @Mooseman: LOL - then you'd find out for sure... – Takkat Feb 19 '15 at 13:21
  • LOL this answer was posted first AND has awesome little gifs, but the above duplicate answer was selected and recieved just as many votes. This sounds like a discussion for Meta – Viziionary Feb 22 '15 at 17:23
16

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.

9

Shake it in your hand. If you hear it sloshing around inside, it's not boiled.

For the future, you may also wish to store your eggs in a vault, where pranksters can not access them.

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    Not a good idea if you're trying to preserve the internal structure of the egg (draining off whites, etc). – corsiKa Feb 19 '15 at 22:24
4

Hold it up to a very bright light. If you can't see inside it's been cooked.

  • Why the downvote? This is a method used in egg packaging industry to check on the quality of the eggs. – Willeke Feb 9 '17 at 21:08
0

It's kind of difficult to make out with just the spinning thing unless you have something to compare with. A BETTER WAY : Give a good spin to the egg along the horizontal axis on a flat surface. If the egg orients itself along the vertical one during its motion, it qualifies as boiled. Simple.

  • Answer seems decently written, will not vote up or down since I don't know if this actually works (I reviewed this). – k-l Feb 9 '17 at 18:46

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