Rotate a boiled egg and you will see the magic happen

Try this and now this experiment. First, boil an egg, then turn it hard on the table with your hand.

If you do it right, chances are you will see this strange phenomenon: when rotating, the egg gradually . stands up, spins vertically, like what you saw in the picture below. .

Do you see anything strange?

But what happened? In fact, this phenomenon has long been recorded, but science takes a long time to study. In 2002, experts came up with a solution, but the answer was a series of extremely complex mathematical formulas.

Fortunately, physicists are now able to give a simpler solution.

"The strange phenomenon of turning eggs has caused a headache for more than 100 years, but it has never been a simple solution," said Rod Cross, a researcher from Sydney University (Australia).

"Those solutions will not help a college student, even a physics teacher."

The problem lies in that for a long time, we don't have the necessary measuring devices. Science cannot separate rotation and friction , making the egg stand up.

But in the end, the answer is already there. According to Cross, the phenomenon is because the egg rotates not only on one axis, but at the same time.

Put an egg horizontally on the table, you will see a slightly raised head. If you try to rotate gently, there will be a horizontal axis along the egg base and perpendicular to the table surface. It is called short axis (or horizontal axis).

But the egg itself also rotates to another axis in the center of the fruit. And because the special shape, the egg center, and the place where the eggs are in contact with the irons, do not overlap. As a result, when the egg rotates, the egg will shake. In physics, this is called "precession".

The egg will rotate in a short axis, but gradually shift to the long axis. That's because the so-called moves on the short axis, causing the axle to shift angle.

But after all, what makes the egg stand up is friction . The long axis will suffer from friction due to contact with the table surface, making the change of angle happen faster. As a result, the egg stood up.

According to Cross's experiment, the progress of the two axes will be expressed by two completely isolated equations. In addition, the experiment also determined that the faster the rotation, the faster the egg will stand. If the rotation is too slow, the friction force produced will not be enough to create this phenomenon.

In the end, many people may wonder why it must be boiled eggs? The reason is that raw eggs are loose, and that makes the heart of the egg unstable. The egg cannot even rotate for too long for that reason.

The result when trying to shoot a raw egg.

The study is published in the European Journal of Physics.