Why Do Car Wheels Appear To Spin Backwards? Here's What's Really Happening

Here’s the explanation as to why car wheels appear to spin backwards when travelling fast.

By Rajkamal

Updated: Friday, February 24, 2017, 14:27 [IST]

Have you ever noticed a car on the move and concentrated on the wheels of the car? It appears like it's moving backwards. Have you ever wondered why? Here's the explanation.

Why Do Car Wheels Appear To Spin Backwards? Here’s Why

The effect is called Stroboscopic Effect, and it is due to the human persistence of vision. Complicated? Let us simplify it further. When something is moving at a fast phase, say for example wheels, or a helicopter's blades, human eyes cannot actually see every point of that motion.

The eyes pick up images 10-12 times every second to create a dotted outline, which is then filled by the mind to make it complete, using experience or just plain common logic.

So when the car wheel is moving too fast - the same case with helicopter rotors - the image will appear as though the object is rotating in the opposite direction, the same direction, slower than its original speed, or even not moving at all.

As the speed of a particular object's rotation increases, the direction of rotation will also change, hence making it look like things are going the opposite direction.