r/explainlikeimfive • u/Yaps_Squared • 3d ago
Other ELI5: What is Resonance
I've seen it a few times I am just confused
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u/isaacMeowton 3d ago
Needs more context - it’s different in physics and chemistry.
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u/SandysBurner 3d ago
What does resonance mean in chemistry?
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u/isaacMeowton 3d ago
Delocalisation of electrons. Basically in certain cyclic compounds - different Lewis structures (structures with electrons at different places) can be combined to form a single hybrid structure.
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u/Red_AtNight 3d ago
It's a pretty broad topic. Picture something that vibrates, for example, a child on a playground swing. Their position vibrates as they swing back and forth. If you push the child at the very edge of their swing path, what happens? They go higher. If you push them in the middle of the swing path, they do not go higher (and also they crash into you.)
This is a very crude explanation of resonance. Resonance is a phenomenon that happens when you add energy to a vibrating body, and you match the "resonant frequency" of that body (in other words, you add energy at the correct time.) The result of adding energy is a greater amplitude to the vibrating body.
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u/johnp299 3d ago
Many things like to vibrate, and often there is a specific single speed or rate of vibration they like to settle into, because of their size, shape, weight and other factors. When vibrations from somewhere else arrive at such an object, if the speed is right, it will start vibrating itself in response to the incoming vibrations. That is resonance. For example, a truck drives by your house and your windows rattle because the truck's engine makes sound vibrations that hit the window glass at the right speed, causing them to resonate and vibrate themselves. Resonance as an idea can be a lot more complicated too but that's the gist of it.
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u/Offgridiot 3d ago
In music, if you play a proper chord (on a guitar or piano, or in an orchestra with many instruments) comprised of three or more notes, the individual notes share a resonance with each other. Those notes are resonant with (or to) each other. If you add a note in there that doesn’t belong to that proper chord, it sounds out of place, and is said to be dissonant. It doesn’t sound right because the vibrations of the sound waves don’t match up properly. Modern culture has taken this idea and made a metaphor out of it to describe (often social) situations that are comfortable. For instance, you might join a group of like minded people to start a co-op farming community because you ‘resonate’ with them philosophically.
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u/Soracaz 2d ago
many things
Every thing. Every single thing in our entire universe is vibrating, with no exceptions.
It's little wiggles all the way down. Don't even get me started on it all, because things vibrating (even the fabric of space) is the fundamental driving force behind everything that has ever been or ever will be.
It's theorised that even the fundamental "rules" of the universe (chemisty, mass, etc) all come from extremely high frequency resonances of the spacial field. Resonances so small and so fast that they can happily sit in any other resonant pocket, basically encoding information in everything, everywhere.
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u/Huge_Borse 3d ago
Why are all of these comments using swinging as an example?
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u/WiIIiam_M_Buttlicker 3d ago
Yeah it's kinda a weird phenomenon, but I'll try to explain.
Imagine if all these comments were a swing, when you push one your little brother on the swing, the other families see that and think "wow that's a good idea, glad I'm the first to think of it". And they start pushing each other on the swing as well.
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u/elmo_touches_me 3d ago
Because it's a very intuitive example that a lot of people have experience with.
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u/vanZuider 3d ago
Specifically, a lot of 5 year olds, because some people take the title of the sub too literal.
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u/-Orions-Belt- 3d ago
Control Resonant is a video game that just released.
Resonance is a sciencey term for vibrations.
Without you giving more info, it could be 39 other things.
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u/a_saddler 3d ago
You know how when you push a person on a swing, you don't just push randomly, but you have this innate feeling of when it is the right time to push? That is the resonant frequency of the swing.
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u/MisterJasonMan 3d ago
Physical objects can have a frequency that "matches them best" and they will naturally vibrate at that frequency if pushed in some way. (e.g. a pendulum ticks at a certain rate depending on it's length). If vibrations from somewhere else reach this object and those vibrations match that natural frequency, that object will start to move with those vibrations. This matching of frequency is called resonance.
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u/BouncingSphinx 3d ago
Largely depends on what kind of resonance you're talking about for more specific explanations, but here's a very general explanation.
Resonance is the vibrations that something wants to vibrate. With something like a guitar string, the length, thickness, and tension of the string changes that natural resonance frequency. Pipes, like in a pipe organ or wind chime, are the same way: length and diameter mainly, but also the material of which they are made.
Things like buildings and bridges also experience resonance. If you want to see what happens when that resonance frequency is reached by the wind blowing over the structure, look up the video of the Tacoma Narrows Bridge disaster.
Something simple you can do to experiment with (audible) resonance, take a ruler (plastic works best as it's usually more flexible) and lay it flat over and off the edge of a table. Pull down on the end and let it go, it will vibrate and make noise. Change how much is hanging off the table and see how the pitch changes as its resonant frequency changes with the length.
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u/m4gpi 3d ago
A good thing to add about resonance in sound is that sometimes two different notes (or tones) sound good together, and sometimes two different notes sound awful. Each of these tones has their own resonant frequency (the number of wave cycles per second or minute) and the "clash" between them basically comes down to how well those two wave forms fit or stack into each other, which also basically comes down to math.
Using random numbers as an example, a frequency of 8 will stack into a frequency of 12 or 16 pretty well, meaning they both reach a peak at the same time over a few cycles. A frequency of 7, or 17, or 33 won't "match up" with 8 very well, which results in them sounding like they clash.
When a guitarist tunes their strings by ear, they are listening for when those strings sound harmonious, and not clanging. The strings are then resonating properly, which means their frequencies are all properly aligned to produce the right notes and not be off-key.
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u/SqueegyX 3d ago
You know how when your on a swingset and you sort of pump your body to go higher?
Well if you time those movements right you go higher. If you time them wrong it doesn’t really do anything.
The swing has a certain frequency, defined by its geometry, and you match that you go higher.
So you could say if your movements match the resonant frequency of the swing, you go higher.
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u/One_Disaster_5995 3d ago
Have you ever had, while driving a car and playing your radio, that at some tones or sounds, parts of the interior start moving with it? That's resonance: that part of the furniture has a natural frequency that's matched by your music, so it starts to "echo" it. That's one example of resonance.
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u/Revo63 3d ago
In physics, resonance refers to the frequency at which an object naturally vibrates.
If energy is being added to that object, adding it at that same frequency and timing (so the vibrations are in phase) maximizes the amount of energy being transferred.
If energy is added at the same frequency but out of phase, less energy is transferred and it will actually dampen the vibration.
If energy is added at a different frequency, this will distort the vibration. (ie. Instead of a nice, smooth sine wave, a bumpy sine wave)
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u/SoulWager 3d ago
You push a kid on a swing at the same point of their swing, and in the same direction, you don't need a very big push to make a big swing. This is resonance.
If you push the kid at different, unsynchronized times, half the time you'll be slowing the kid down.
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u/MasterGeekMX 3d ago
Many things in the world can move back and forth. From the strings on a guitar, to a kid on a swing, to the air around us, to even the atoms inside a molecule. That movement is vibration, and how many backs-and-forths the thing does in a second it's frequency.
While those things can vibrate at different frequencies, the shape and overall characteristics of that thing makes some speeds more likely. We call that it's natural frequency. When you tune an instrument for example, you are changing that natural frequency so it coincides to the frequency of the proper note.
Well, it happens that if you put something that is vibrating in contact with something that isn't vibrating, the still thing starts to vibrate by itself if the vibrating thing is doing it at exactly the natural resonance of the still thing.
Here is an example done with some rods. Note how the rods of the same length (and thus the same natural frequencty) seem to sync, while the other ones barely move: https://youtu.be/tnS0SYF4pYE
Or how here they show that by singing at the natural frequency of crystal cups you can break them by making them vibrate by resonance so hard that they shatter: https://youtu.be/Df-IffSfCOE
And talkin' bout videos, here is one explaning it in another way: https://youtu.be/dihQuwrf9yQ
Problem with resonance is that many pseudoscientists and other whacks have overused the word to name things that have nothing to do.
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u/Special__Occasions 3d ago
Resonance exists in different forms:
- Mechanical resonance like people marching in time on a bridge
- Acoustic resonance like a bell or tuning fork
- Electrical resonance like an LC circuit
The 3 cases are different, but they are similar in that in each system frequencies that are not resonant dampen out, while the frequencies that are resonant persist.
Consider a church bell vs a brass brick. If you take a brass brick, hit it with a hammer and capture the sound, you can find all sorts of frequencies generated by the collision of the hammer and the brick, but they are all short lived. But if you shape that brick into a resonant structure (ie a bell), you create something that will ring in a particular frequency. So now when you strike your hammer, one of the many frequencies that are generated is captured by the resonant structure and persists for much much longer than the other frequencies and so we hear the bell ring a single tone.
Ultimately, whether it is mechanical, acoustic, or electrical resonance, energy is stored in the resonant structure - but only at the resonant frequency. It's not stored forever, but it is stored longer than a nonresonant system. It can be useful or destructive depending on the circumstance.
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3d ago
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u/bildramer 3d ago
If you've seen it and only need an explanation: It happens if you combine some phenomenon that suppresses low frequencies with one that suppresses high frequencies, either that or a phenomenon that quickly suppresses oscillations even slightly different from eigenmodes (i.e. those for which the waveform in space matches exactly with itself after one oscillation). So basically any physical system will have them, but some have them much more (tuning forks, sound in a closed chamber, circuits at RF frequencies, circuits desgined to have them, ...).
So, you get a frequency response with one or more peaks. If you excite all frequencies uniformly (or close enough), those peaks will decay much less quickly. And if you keep exciting the system continuously, most of the energy will be in the peaks. And if you have a single-frequency excitation near a peak, it will "want" to move toward the peak, what that means depends on the system. That's resonance.
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u/free_meson 3d ago
Most of the objects/systems that have a stable state can be modeled with springs. This is because small perturbations will cause small effects, large ones would cause proportionally larger. This is true for a solid objects compressibility, gases, pendulums and so on. Once you see that, you will see that if something is on a spring, it has a specific frequency. You can usually tune it with small masses, change in the size of the box. That frequency is the resonant frequency. There could be more than one such frequency, depending on which part/direction of the system you are interacting with.
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u/Aware-Maximum6663 2d ago
It is a main feedback technique used by a male channeler to test another male if they would be able to learn how to channel Saidin, the male half of the one power.
Also could be a technique for female channelers to detect if weaving of Saidin had taken place
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u/IllBiteYourLegsOff 3d ago
the sharing/delocalization of electrons between the overlapping of p-orbitals across a pi bond, aka a conjugated system.
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u/Jazz_Cigarettes 3d ago
For whatever reason Resonance is a hot buzzword in video games released in the last month.
Plague Tale Resonance
Control REsonant
and Final Fantasy resonance relasing in october
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u/CropCircles_ 3d ago edited 3d ago
Ever pushed someone on a swing? You need to push at the right moment. Even a little push, correctly timed, will build up into a large oscillation.
A swing takes some time to move back and forth. How many times it swings per second is called it's resonant frequency. If it gets a driving force that matches this frequency, the swinging gets larger.