On pages 122 to 125 of the book Beyond the Rollercoaster, there is a mention of some videos being demonstrations of the phenomenon of resonance. Here they are, together with some of the text, for your pleasure and amazement.
Resonance is a well-known and very important principle in physics. It is crucial to understand resonance in order to understand how things are connected in the bigger picture. It’s the invisible glue that binds us all together, for better or for worse. Resonance is very powerful.
A good example is the Tacoma Narrows Bridge in Washington State, with 1.9 km long, was one of the largest suspended bridges built at the time. In 1940 the bridge collapsed in a dramatic display as average winds of 65-75 km/hr (35-46 mph) produced an oscillation which eventually broke the construction. It turns out, the wind was blowing at the same frequency as the natural resonance frequency of the wires that were holding the bridge. The resonance between the wind and the bridge caused the bridge to fail. The bridge collapse has been recorded on video:
Video title: “Watch the amazing “Gallopin’ Gertie” November 7, 1940 film clip.”
A similar problem happened with the London Millennium Footbridge, which is a pedestrian-only steel suspension bridge. It didn’t collapse but it had to be closed for several months in order to make structural changes, which cost over £5 million. One of the opening scenes in the movie Harry Potter and the Half-Blood Prince (2009) shows that bridge collapsing, although the cause of the resonance is different in the story than real life.
Video title: “London Millenium Bridge Opening”
A LITTLE BIT OF PHYSICS
Why does your dog start acting happy when you start on your way home? Is it a 6th sense? I don’t think so. Unless what we call the 6th sense actually is resonance. Your dog resonates with your thoughts of being home while you are on your way home. The same happens when you think of someone minutes before you receive this person’s phone call. Why do plants grow better with classical music? Maybe it’s because that music is closer to the plant’s natural resonance frequency. How do migratory birds or whales know where to go? They resonate with the magnetic field of the Earth.
Everything can be affected by resonance. We use it all the time without realizing it. In order to understand resonance, you must first understand what a vibration is and how one object can influence another object via its natural resonance frequency.
Let’s start with the concept of vibration. A vibration is the result of the energy radiated by a certain object. Think of when you throw a rock in a calm pond: the ripples are the vibration.
A vibration has a frequency, which is measured in oscillations per second. That’s the number of ripples per second in a stationary location on the pond. I will use the terms vibration and frequency interchangeably in this context.
When you look at a landscape, you can appreciate its intricate details because your eye perceives many variations of colors due to the different frequencies reflected by each part of the landscape.
Everything around us emits a frequency. Without a variety of frequencies, you could not see, hear or touch anything. It is the means by which you interact with your environment.
When I was in college, one of my physics teachers suddenly stopped right in the middle of explaining the principle of resonance, took a breath in, and exclaimed in a climax of excitement: “Everything is about resonance. Do you get this? It’s all about resonance.” This phrase struck me so strongly that I stopped breathing for a few seconds, taking it in. I felt a cold shiver running up my spine. I instantly knew that one day this knowledge would have a much bigger impact than I could perceive at the time.
Amongst all the frequencies a certain object can resonate with, there is one that will affect it the most, and that is its natural frequency of vibration, which is also called the natural resonance frequency of the object.
An external periodic force occurring at the same frequency as the natural resonance frequency of an object will bring that object to vibrate in synch with that frequency, which will raise the amplitude (or intensity) of the object’s vibration. This is called resonance.
An example that is easy to understand is when you push a child on a swing. Each time the swing comes back, you give it another push. This means that at each cycle of the swing, you are adding more energy to the energy that was already in the swing at the same frequency, so the amplitude of the movement gets larger and larger every time you push.
There is resonance between the push and the swing.
Laser beams work in this way too: all the individual light beams of a laser are generated in the same frequency as their resonance frequency, so the power of the resulting laser beam is much greater than the power of a scattered and random light beam such as sunlight. It’s the reason why surgeons can perform certain operations without making an incision: they tune the laser beam to the resonance frequency of the tissue they want to affect, and it leaves other tissues which have a different resonance frequency unaffected.
Engineers have to take into account the resonance frequency of every major structure they erect. Most skyscrapers are built with dampers and counterweights that will change or scramble their resonance frequency to make them safer in case of an earthquake or if strong winds would happen to blow just at that specific frequency.
Video title: “Simulation of what happens to tall and small buildings in earthquakes!!”
It doesn’t matter how big or how strong that object is, anything will be affected and can even break if you replicate the resonance frequency for that object.
Video title: “Mythbusters Jaime Vendera Jamie Vendera Rock Breaking glass”
Resonance is everywhere. It influences most interactions in the universe. It is so basic that we tend to forget how important it is. Resonance not only affects inanimate objects, it also allows human beings and animals to communicate between themselves. Only 7% of communication is apparently done through words, the rest is unconscious. Much of it is through resonance.
A unique thing about human beings is that we can interact through many frequencies at the same time. We are frequency receiving and producing machines: we can respond or generate a large range of frequencies, although there usually will be one, or a handful, that is dominating at any point in time.
To read more about resonance and how it affects your happiness, get the book Beyond the Rollercoaster.
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For the science hungry poeple out there, here are a few more videos…
FULL course on resonance:
Video title: “Professor Ephraim Fischbach demonstrates resonance in this video from Thinkwell’s online Physics series”
Video title: “Resonance oscillating a wine glass by playing sound at its resonance frequency:”
Breaking a wine glass using sound :
Girl breaks glass with voice
another one, Breaking Glass with Voice :
High Notes That Break Glass
matter being affected by resonance
Dr. Hans Jenny in his study of Cymatics – study of matters pertaining to waves:
The plane is vibrated at some specific frequency. The waves travel across the plane and at some places they add together and at other places they cancel out. Where they cancel out the salt stucks because there is no vibrations and at other places it just gets vibrated away.
Resonance Phenomena in 2D on a Plane
Tibetan Singing Bowl – Water Time Distortions
cornstarch lifeform 80Hz
Creature in the Sonic Liquid
How to make a cornstarch monster in your own home.
Standing waves in salt
Non-Newtonian Fluid on a Speaker Cone
conceptual physics Demo of Resonance
Paul Hewitt demos sympathetic vibration & resonance of sound
waters standing wave transitions at 100 cycles per second demonstrating clearly dynamics of energy/matter conversions
Cymatics – Bringing Matter To Life With Sound (Part 1 of 3)
These original films of Cymatics experiments were made in the 1960′s by Swiss scientist, Dr. Hans Jenny.
They are now available on a single composite DVD, entitled Cymatic SoundScapes: Bringing Matter to Life with Sound. www.cymaticsource.com
Ground Resonance in Chinooks
Short Version: Bad vibrations build up in the frame of the aircraft which is amplified until the helicopter goes “boom.”
Long Version: Ground Resonance is an aerodynamic phenomenon associated with fully – articulated rotor systems. “Ground” implies the airframe must be in contact with the ground. “Resonance” refers to the natural vibration frequency of the airframe resulting from the design and manufacturing process. Each part of the airframe, including the rotor system, vibrates at a certain frequency. During the development process, engineers will design the helicopter in such a way as to avoid having the fuselage and rotor system vibrate in sympathy with each other. Otherwise, the helicopter would be difficult to control. Instability can occur when the lead-lag frequency of the rotor couples with one of the natural frequencies of the fuselage, usually due to a shock to the airframe.
Ground Resonance Test – Amazing videos are here
Caltech: The Mechanical Universe – 17 – Resonance