Physics and Technology – Physics – Vibrations and Waves
Most areas in physics investigate well-defined issues—for example, electromagnetics or thermodynamics.
The study of vibrations is different: Practically any vibration or oscillation can alternate between a high or low intensity.
This explains why this area of research is so interesting and relevant to the entire field of natural sciences.
Physics and Technology – Physics – Vibrating Systems
Just as the Beach Boys sang Good Vibrations in 1966, vibrations can be passed on in physics as well—sometimes resulting in harmony and some- times in a catastrophe.
Physical vibration can be much more than a sweep of a pendulum or a child on a swing. For example, atoms of a carbon dioxide molecule are swinging against each other continuously. Vibrations inside the Earth tell us much about its structure, but they can also cause damage through earthquakes. The “inner clock” of humans, animals, and plants runs on periodically recurring chemical reactions.
The rise and fall of stock prices as well as poll ratings of politicians are also familiar examples. Regardless of how diverse the swinging oi vibrating systems in nature and society may be, the same physical and mathematical methods of description apply to all of them.
Resonance: from sound to catastrophe
As soon as we hear a rhythmic sound nearby, we will often begin to unconsciously move along with it. Not only humans can be made to swing or vibrate, the same can be done to a tuning fork or a blade of grass. The scientific expression for this phenomenon is “resonance” (from Latin resonare: “resonate”). Not every sound causes an object to resonate.
A soprano singer has to hit the note precisely so that it will break glass. We have to push our children on a swing in precisely the right rhythm that allows the swing to go even higher. Why? Because of the so-called natural or free vibrations of the glass or the swing. Each system has certain rhythms (scientifically, this is referred to as frequencies).
If such a free vibration acts upon the object from the outside, then it will vibrate more and more— in the worst case, it may even vibrate until it is mechanically destroyed.
Taipei 101
The Taipei Financial Center, called Taipei 101, is a mega- high-rise building in the Taiwanese capital Taipei, which is situated in a high-risk area for earth-quakes and hurricanes. To protect the building from suffering damage, the architects and engineers designing the building decided to place a huge ball weighing several tons in one of the top floors.
Vibrations of the building caused by waves from earthquakes or hurricanes are dampened by the ball’s easily induced movement.
THE SINE FUNCTION
The study of vibration is relevant to mathematics, physics, and mechanics. The simple form of vibration with a constant frequency and constant maximum deflection is described by the mathematical sine function.
The plotted function looks like a curve with gentle waves- its Latin name sinus is derived from this shape.