Stroboscopic effect is what makes one wonder

Surely everyone used to look at the car that drives forward, and there is a feeling that the wheels are moving in the opposite direction or do not move at all. Or, for example, in some movie a helicopter flies, and it seems that the blades do not rotate. This is the stroboscopic effect, which is a rather difficult concept in the field of physics. If you delve into the definition, then from the Greek language, this phrase will mean the next set of concepts "whirling" and "watching" (also can be translated as "whirlwind" and "consider"). And this is a classic optical illusion of sight, which is caused by a number of factors.

What is this effect

The stroboscopic effect is nothing more than an optical illusion of vision, which occurs with a distorted perception of moving parts. And we can not say that in physics, there are two main types of this effect:

1. The first type is characterized by the fact that when observing rapidly changing individual phases of the movement, an illusion of continuous movement arises. This is associated with the peculiarities of visual perception. So, for example, if the time between the appearances of some individual images is much smaller than the gap, then the images merge, and the motion is perceived to be continuous. It is on this effect that movement in the cinema is built, provided that the frequency of filming and projection is approximately equal to the frequency of the process that is taking place.

2. This effect of the second type implies that under some specific conditions there will be an illusion of rest of the object, which actually moves, and the example with the helicopter determines precisely this type of stroboscopic effect. But here a special role is played by lighting.

Such optical illusions are actually observed by everyone, just someone does not pay attention to it, and someone simply does not explain the physical ground of this effect. Nevertheless, difficulties in the perception of such actions are due to a number of biological factors, in particular, it is a question of the features of the construction of the visual organ and perception of the surrounding reality - this is called the inertia of vision.

Vivid examples of this effect in real life

In fact, if we talk about the stroboscopic effect and about where it can be observed in real life, then the examples are not easy to give. And the most obvious example that you can watch for everyone is a disco. How does this effect manifest on the dance floor? Naturally, the clubs have special lighting and a lot of mirrors. All this contributes to the fact that when people dance, there is a feeling that they are moving like robots. Naturally, this is due precisely to the flicker of light and to the peculiarities of its perception by the human organ of vision.

Also, if you have a slow-motion camera, you can observe a stroboscopic effect if you take off the dripping water from the tap. As a result, you will see that one drop was with certain fragments at all intervals, and it fell, as it seems to us, smoothly.

Quite a lot of examples of this effect are reproduced by physicists in laboratory conditions. To do this, reproduce a certain light with pulsed sources, with the ability to adjust the frequency - these are strobe scopes. So, with these studies, one can observe, for example, the peculiarities of the motion of the fan blades. In specific lighting, there may be a feeling that the blades move in different directions with a certain periodicity or even become stationary at all. Also with the help of a stroboscope you can observe the movement of the ball and the features of its trajectory. Such an effect and strobe, in particular, is used not only to determine some theoretical moments, but also useful for the production of certain parts of machines.