1, all three gyros can rotate.

2. Among the three gyroscopes, matchsticks are tied to the center of the cardboard and rotate stably. The gyro made of round cardboard rotates most stably and for the longest time.

3. The gyro rotates on the circumference.

Gyroscopes all rotate around one axis (matchstick).

When the gyro rotates, its size and shape do not change.

When the gyro rotates, it not only rotates around its own axis, but also makes a conical motion around a vertical axis. In other words, the gyro rotates around its own axis and precesses around the vertical axis. In other words, the gyro does not stand vertically above the ground, but has a certain deviation from the ground normal and a certain inclination to the ground. Therefore, the moment of gravity on the gyro is not zero, and the precession angular momentum of the gyro can balance the effect of heavy moment, so the gyro will not fall to the ground when it rotates.