How to Tell a Raw Egg from a Hard-Boiled Egg
So you cooked several hard boiled eggs and returned them unpeeled to the refrigerator. The next thing you know the eggs you have cooked have been placed back in the carton of eggs. How can you tell which eggs are the hardboiled eggs?
Difference in Momentum
Simple. Take the eggs out one at a time and carefully spin them (like a top) on a flat surface such as your counter top. As the egg is spinning touch it with one finger on top of the egg to “stop” the egg from spinning. Release the egg quickly. If the egg continues to spin then it is an uncooked egg. If it stays motionless it is a hardboiled egg.
Reason. The liquid egg in side is still in motion for a raw egg. Even though you stop the egg from the outside the momentum of the liquid in the egg causes the egg to spin. This momentum is lost if the egg is hardboiled. As you stop the hardboiled egg the interior of the egg stops too therefore the egg will not continue spinning.
This can also be used as a simple science experiment for school age children to show how momentum works.
Do you have any tips on how to tell a hard-boiled egg from a raw egg? Our readers would like to hear from you, please feel free to start a discussion.