Tail Wags Dog

Lecturer tries to swing baseball bat while standing on turntable.


Coriolis Force

What it shows:

The Coriolis force is a pseudo force existing in a frame that rotates with constant angular velocity to a reference frame. It acts on a body moving in the rotating frame to deflect its motion sideways. Here the audience sits in the reference frame, while two volunteers on a rotating platform experience the coriolis force by trying to basket a volleyball.

Read more about Coriolis Force
Pascal's Paradox

What it shows:

Three containers are filled with water to the same depth, and each has the same base surface area (see figure 1). Since the pressure and area are the same in each container, the force should be the same (pressure = force/area). pascalSo how come the scales...

Read more about Pascal's Paradox
Standing Wave in Metal Rod

An aluminum rod, supported in the middle, rings for a long time in its longitudinal mode.

What it shows:

Longitudinal standing waves in solids.

How it works:

A metal rod is not unlike an organ pipe with both ends open. Holding it exactly in the middle will force the simplest, or fundamental, mode of vibration -- the ends will be free to vibrate maximally and the center will be a node. The fundamental frequency happens to be 2.26 kHz. As with a pipe open at both ends , the rod will vibrate at all the odd as well as even...

Read more about Standing Wave in Metal Rod

What it shows:

The effect of length, tension, diameter, and kind of material on the pitch of a vibrating string is demonstrated. One may also show the harmonics of a vibrating string.

How it works:

The sonometer is a long hollow wooden box along the top of which are stretched one or more strings rigidly attached to the box at one end, with provision at the other for changing their tension. If there is just one string, it's known as a monochord. The monochord illustration is from John Tyndall's book entitled Sound, (...

Read more about Sonometer
Magnetic Levitation

What it shows:

A magnet tethered over a spinning aluminum disc levitates due to induced currents in the disc.

How it works:

As the disc spins, electrical currents are induced in the aluminum as it moves with respect to the magnet. These induced currents create a magnetic field which, in accordance with Lenz's law, opposes the field of the magnet. The magnetic repulsion causes the rider to levitate about 1cm above the disc. Lenz's law also says that the induced field will oppose the motion that causes it. The magnet therefore tugs...

Read more about Magnetic Levitation