Thermal Physics

An old bomb calorimeter made by the Parr Instrument Company for show-and-tell. Circa 1964.

Copper has positive temperature coefficient; light bulb gets brighter when copper leads are dipped in liquid N₂.

What it shows: 

Copper has a positive temperature coefficient (≈ 3.9×10^-3 per ˚C), which means that its resistance drops with temperature. Here...

Shoot the ring through the roof after dipping it in liquid N₂; Lenz's law induced EMF in metal ring.

What it shows: 

The induced current in a metal ring is dramatically increased by lowering the ring's temperature.

How it works: 

Here is an extension of the R...

What it shows:

A superconducting material in the presence of an external magnetic field excludes that field from its interior. This is shown by levitating a magnet above a high-temperature superconductor.

Photo courtesy Clive Grainger

How it works:

We have a...

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...

What it shows:

Mechanical properties of some materials change dramatically with temperature. These changes have entertaining effects on everyday objects by taking them from room temperature 300K to the temperature of liquid nitrogen 77K.

How it works:

Place...

Drum evacuated by vacuum pump; crushed by atmospheric bombardment.

What it shows:

With an air pressure of 10⁵ Nm^-2 at sea level, even a heavy duty oil drum will be crushed if it has nothing inside to balance the pressure.

How it works:

The screw cap on the...

Smoke cell under microscope; smoke particles seen bombarded by air molecules.

What it Shows

Brownian motion shows direct evidence of the incessant motion of matter due to thermal energy. Here we use the random bombardment of smoke particles by air...

Simulation of molecular motion (Brownian, diffusion, etc.) with ball bearings on shaking table.

What it shows:

Two dimensional simulations of molecular dynamics and crystal structure using ball bearings. It can be used to show qualitatively the dynamics of...

Food coloring in glycerine is mixed by turning a drum, then unmixed by reversing. Has entropy decreased?

What it shows:

Ink is squirted into a fluid and mixed in until it disappears. By precisely undoing the motions in the reverse direction, the ink...