Question 1: how does animation come into being: generally, the video we are exposed to is 30 or 60 frames per second, that is to say, 30 or 60 different coherent pictures are switched in one second. So the principle that our gyroscope can form animation is also in accordance with this law.
Question 2: why can't we see the gyro animation with the naked eye: because the refresh frame rate of our naked eye is very high, when the gyro rotates again, we can't see the fixed frame image when we see the rotation.
Question 3: why is there animation sometimes and no animation sometimes? Because when you choose the video format of 30 frames per second, the gyroscope needs to rotate 30 turns per second / 6 (6 pictures) to freeze to the picture and generate animation.
Question 4: why do you have to be in the sun to make an animation? The last question mentioned that only the freeze frame picture can form an animation, so we have to take a single picture as an example. A picture is composed of aperture, light sensitivity and shutter. When we take a picture of a moving vehicle at night, we always have a drag effect because the light is too dark and the shutter is not fast enough. Then, when the gyro rotates at a high speed, we must have enough light to make the mobile phone shutter automatically meet the high shutter speed, so as to freeze every frame in rotation