Have you ever wondered how Radio pick certain frequencies to play your favourite channel or why did the glass break down in an orchestra concert? Have you ever felt bridge vibrating, when you walk on it? This is all due to resonance.
Resonance is a phenomenon in which an external force and a vibrating system, forces another system around it to vibrate with greater amplitude at a specified frequency of operation. The frequency at which the second body starts oscillating or vibrating at higher amplitude is called the resonant frequency of the body.
Let’s see the examples of resonance that occurs in our everyday life.
A playground swing is a familiar example of the resonance. When we push the swing, it swings forward and backwards. If a series of regular pushes are given to the swing, its motion can be built enormously. The man who is pushing the string has to match the timing of the swing. The pusher has to sync with the timing of the swing. This cause the motion of the swing to have increased amplitude and the swing will go higher. Once when the swing reaches its natural frequency of oscillation, a gentle push to the swing helps it maintain that amplitude of swing throughout due to resonance. We call this in-sync motion, Resonance. But, if pushes are given irregular, the swing will hardly vibrate, and this out-of-sync motion will never lead to resonance, and the swing will not go higher.
A Guitar makes sound entirely by vibration. In an acoustic guitar, when you pluck a string, it vibrates back and forth, transmitting sound energy into the hollow wooden body of the guitar, making it (and the air inside) resonate and amplifying the sound (making it considerably louder).
Whereas in an electric guitar, when the musician strike to the string, it oscillates and the electromagnetic device in the guitar turns this oscillation into an electric signal that it sends to the amplifier. The amplifier sends oscillations on to the speaker. If the frequency of the speakers matches to vibration of the guitar, it results in the sound which is called audio feedback.
Pendulum works the same as swing. If we push the pendulum it will move back and forth. continuous pushing at the proper timing will cause an increase of the speed of the pendulum to move back and forth. If regular pushes are given to the pendulum, its motion can be built enormously.
4. Singer Breaking A Wine Glass
Have u ever watched or heard about shattering of a wine glass in orchestras? If yes then this is all due to resonance. The natural frequency of a glass or any other object is determined by its shape and composition. If the singer’s voice, hits the resonant frequency of the wine glass, transfer of energy will occur. However, the full transfer of energy can break the glass, causing it to shatter.
A group of soldiers while marching on the bridge are asked to break their steps very often. Their rhythmic march can set extreme vibrations at the bridge’s natural frequency. If their synchronized footsteps resonate with the natural frequency of the bridge, it can shake the bridge apart. So, When designing such structures, the engineers ensure that the resonant frequencies of components are different from that of other oscillating components. The biggest example of this is Tacoma Bridge Collapse, in which the frequency of the air matches with the frequency of the bridge, leading t its collapse.
6. Music system playing on the high heavy beat
Have you ever noticed the walls and furniture of your home vibrating when you play music on heavy beat? This is because the natural frequency of the furniture get resonated with the frequency of the sound of the music and hence causing them to vibrate.
7. Singing in shower
People who are not very good at singing sound much better singing in the shower because the pure notes they do emit are resonated in a shower cubicle. The bathroom is closed and sometimes small, as you sing the sound waves hit the walls more frequently causing the wall to vibrate since walls are parallel to each other.The reflected sound hit each other, thereby causing the wall to vibrate at your natural frequency and the louder sound is transmitted.
When we turn the knob of the radio to our favourite channel, we are changing the natural frequency of the receiver. The natural frequency of the receiver then matches to the transmission frequency of the radio station. When two frequencies match, energy transfer occurs and we can listen to the selected channel.
9. Microwave Oven
The food is cooked very efficiently, evenly and quickly in a microwave because of resonance. The microwave oven has a certain wavelength and frequency. And like all other objects, Molecules of water and fat also have a resonant frequency. At a certain frequency, the molecules absorb wavelengths and start vibrating, causing cooking and heating up of food.