So, Everything Resonates!
Have you ever flicked that ruler over the edge of a desk while holding it firm at the other end?
It vibrates back and forth, really quickly. So quick, in fact, that we can hear the sound it makes. Reduce the length hanging over the edge and the pitch (resonant frequency) increases. Flick it a little bit and it makes a soft sound. Flick it harder and it makes a louder sound. Flick it too hard and it breaks (the applied force is in excess of the material’s ability to “store and release” that initially applied force).
Whether it is a ruler, a tuning fork or wine glass, they each have the ability to “store and release” an applied initial force. In fact, when the material “springs back” releasing the stored energy, it becomes the next applied force, but in the opposite direction. This repeats over and over again at a rate dictated by the properties of the material itself. This rate of cyclic repetition is the resonant frequency of the material. Theoretically, it should resonate forever without the need to flick it ever again. In reality, energy is lost every time the energy is “stored and released”. Maybe by moving the air around it (as sound) or energy lost as heat through other forms of friction. Needless to say the vibration decays and eventually stops altogether. A ruler stops after just a second or so. While a tuning fork can continue to resonate a minute or more.
If we consider a wine glass, specifically running your wet finger around and around the rim of the glass it starts to resonate at its Natural Frequency. Don’t stop, keep running your finger gently around the rim. As you do this, it puts more and more energy into the glass. As the energy in the glass builds, the sound gets louder and louder eventually shattering the glass. But you were only applying a constant small energy input. The glass material could not “store and release” any more energy, which lead to its physical destruction.
I know it’s getting a bit boring.
But consider, if everything has its own resonant frequency. This “resonance” can be exploited.
The micro-wave oven in your kitchen injects large amounts of radio wave (500W to 1000Watts) at a frequency of 2.4GHz. That’s a vibration around 1,000,000 times faster than that wine glass. Why, because the resonant frequency of water molecules happens to be 2.4GHz so it excites the water in the food making the water molecules themselves vibrate. The injected energy is lost very quickly as a type of friction. This friction causes a large amount of heat to be generated at the molecular level within the food itself. The more water molecules the food has in it, the quicker it heats up. That’s why the plates themselves don’t get hot, other than from heat transfer from the food on them.
But sometimes resonance is a problem. Many bridges and buildings have collapsed because of resonance. Wind and earthquakes can inject large amounts of energy into the structures. When this happens at a low frequency similar to the natural resonance of the structure, it starts to sway back and forth. If the movement becomes too much, the structure fails and it collapses.
I read how planets resonate against each other’s orbits within a solar system. But, I wonder if solar systems resonate within their galaxies, and so on in the universe. The natural resonant frequency would of course be incredibly (and immeasurably) low.
We have, in fact, lived our whole lives in an electro-magnetic resonance of 7.83Hz right here on Earth. It’s called the Schumann Resonance. It’s created by the Earth’s magnetic field.
It is only reasonable to consider that humans, animals and plants have been evolving over millions of years within this constant 7.83Hz resonance. I am sure that this has affected our overall health and mental wellbeing today.
I am not sure what resonates with you, but at least I know what “Resonates” with me!