Low Temperature Phenomena

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...

CO₂ and He balloons in liquid nitrogen.

What it shows:

Cooling a gas causes a proportional decrease in volume with the drop in absolute temperature. A gas such as helium, which remains close to ideal at low temperatures, shows a four-fold decrease in volume...

What it shows:

A changing magnetic flux induces a current in a metal ring; the magnetic field due to this current opposes the primary field, repelling the ring and flinging it into the air. That's the simple "hand waving" explanation for the beginner...