Faith in the conservation of energy is tested by taking the demonstrator's nose to task.

What it shows:

The principle of conservation of energy ensures that a pendulum released at a particular amplitude will not exceed that amplitude on the return swing. A lecturer's faith in their subject is put to the test using a 50lb (22.7kg) iron ball.

How it works:

Technique is very important here. The best method to employ is to stand with your back against the blackboard with your head also touching the board. This ensures that you don't lean forward after release....

Plane of pendulum oscillation appears to change due to rotation of Earth.

What it shows:

Due to the rotation of the Earth, the plane of oscillation of a pendulum will rotate with respect to the surface beneath it. We expect a rotation of about 10˚/hr at our latitude of 42.˚

How it works:

Here the observer standing on the Earth resides in the reference frame, with the swinging pendulum oscillating in a rotating frame. From the pendulum's point of view, it keeps oscillating in the same plane, but the Earth spins below it. The deflection from its original plane...

Large speaker with signal generator/amplifier destroys a wineglass; stroboscopic illumination shows vibration mode.

What it shows:

Sound waves of the right frequency are used to excite a wineglass in one or two of its normal modes of vibration. Stroboscopic illumination makes it possible to actually see the vibrations in apparent slow motion. When the intensity of the sound is increased, the large undulations of the glass exceed its elastic limit and cause it to shatter. This can be done in the fundamental or next higher normal mode of vibration ... a beautiful and dramatic...

What it shows: 

Bell plates are polygonal-shaped flat pieces of sheet metal which, when held in the hand and struck with a beater, produce a pleasant, sustained, slightly bell-like tone. Compare this to any arbitrary shaped piece of metal which produces a "clunk" when struck. The sound of the bell plate depends strongly on its shape and even the most modest change in the symmetry (like snipping off a corner) or proportions will make it go clunk when struck.

How it works: 

Why does a particular shape ring so well,...