Why do you sometimes see car wheels reverse?
Is to see an object, the image of an object will do a short stay in the retina, the residence time is about 0.08 S. and a eight car spokes start from rest, if at 0.08 S when asked in the rotation angles of car is just 45. Then we just see the wheel "do not move", if in 0.08 S time, the vehicle rotation angle is 0 < 0 < 22.5.
In real life, we see the wheel "upside down" is the result of human visual persistence.
We see the wheel is "upside down". Therefore, we often feel more fans, car wheels and other sports more and faster life, to forward more quickly, then slowly to "turn", and then slowly forward. This is the same reason.
