Image on black and white television is deflected by a magnet, not unlike the Maltese Cross.

What it shows:
The television is basically a sophisticated cathode ray tube. The electron beam in the TV is influenced by magnetic fields in the same way as in Crookes tubes.

How it works:
The image on a black & white TV is formed by a single electron gun scanning the screen. Holding a strong magnet to the side or in front of the screen deflects the beam from its regular sweep pattern, distorting the image.

Setting...

Dull at room temperature, rings clearly after immersion in liquid nitrogen.

What it shows: 

A lead bell, dull sounding at room temperature, rings brightly when cooled to liquid nitrogen temperatures.

How it works: 

A lead bell at room temperature is dull in more ways than one. But its elasticity is temperature dependant, with an increase in elasticity as its temperature decreases. This increase in elastic modulus narrows the resonance response with frequency and increases the quality Q of the lead as...

What it shows:

Allow a board to rotate under the force of gravity and the free end will accelerate at a rate greater than g. Relation between angular acceleration and linear acceleration seems to give free-fall paradox.

How it works...

What it shows:

The magnetic field lines of the Earth can be represented by the field lines of a bar magnet.

How it works:

The Earth's magnetic field is basically a magnetic dipole. It can therefore be represented to first approximation by the field of a bar magnet. The shape of the field lines can be highlighted by the sprinkling of iron filings, or by the use of plotting compasses. The latter method has the advantage of showing the variation of dip angle with latitude, with the lines of force running parallel to the surface of...