What is resonance?

Quite usual picture - concert hall, violinist-virtuoso on stage, the hall is filled with numerous music lovers, who listen to the enchanting sounds. Without touching the skill of the performer, everything that happens is made possible by the effect of acoustic resonance. So what is resonance?

At the mention of this term, the old story of the destruction of the bridge by a company of marching soldiers is immediately recalled. The soldiers, having ascended on it, continued to go in a drill step, in the leg. As a result, the bridge collapsed.

Or the most common picture - a child on a swing. And someone next to them, rocking them. Minor effort, applied at the right time, allows you to achieve a large amplitude of oscillations and deliver a great pleasure to the kid.

Without going into a mathematical description of what is happening, let's try to understand qualitatively what is resonance. The physics textbook defines this effect as an amplification of the amplitude of the system's oscillations when the frequency of the external action and the natural frequency coincide. A little explanation. The oscillation frequency is the number of vibrations per second.

Yes, it is not entirely clear, words like all familiar - resonance, physics, frequency of natural oscillations. What does it mean?

For simplicity of perception, let us recall another example - between the two supports (let it be the two banks of the stream) lies a long wide board, it is slightly rocked, oscillates, but it looks reliable. Go through the stream like it's just, get up on the board and go. But here's what a misfortune. At some certain speed of movement, or in other words, the frequency of steps, the board begins to swing violently, threatening to throw the walker away. In this case, the resonance conditions are again fulfilled - the frequency of the oscillations of the board itself coincides with the frequency of pedestrian steps. As a result, the amplitude of the oscillations increases significantly, resulting in an increase in unexpected water procedures.

This phenomenon is extremely widespread in a variety of areas. In electronics, medicine, music, which is where the description of the resonance effect began. This phenomenon is often useful, allowing, for example, to amplify a weak signal. The sound of the violin string is amplified by its body, which acts as a resonator, i.e. Amplifier at a certain frequency. And the sound of the violin itself is enhanced by the good acoustics of the room.

A slightly different application of resonance is the amplification of the signal of the radio station. Again, everything is simple. Radio waves bring the signal to the antenna, from there it enters a special input circuit, changing the parameters of which it is possible to amplify the signal of the desired frequency. This is what we are doing when we twist the tuning knob of the receiver in search of the radio station we need. As a result of this amplification, the signal of the allocated radio station becomes stronger and is successfully perceived by the receiver.

From the examples given, the answer to the question about what resonance is becomes clear. This is a general increase in effort, obtained by synchronizing the capabilities of the system itself and external impact. As a final example - an attempt to get out of the mud on the car by "swinging". The driver starts to move alternately on the machine forward and backward. Back, then acceleration forward, in case of failure again, acceleration, but already back, and again forward. With this approach, engine power is added to the inertia of the motion and in many cases allows you to overcome a difficult place.

Even the modest number of examples given is sufficient to understand how widely the phenomenon of resonance is used in engineering and everyday life.

In the given material the answer to a question that such resonance is given. Examples of the manifestation of resonant phenomena in various fields of technology and culture are considered.