Physics Demo Videos: Thermodynamics

Physics Demo Videos: Thermodynamics

For other videos from our demonstration collection, please visit Physics Demo Videos. You may also wish to view our Video Lecture Series for short tutorials on topics from first year physics.

Phase transitions

Liquid Nitrogen. When nitrogen gas is cool enough, it becomes a liquid. This liquid can then be used to freeze items such as flowers.Freezing flowers in liquid nitrogen

Thermal expansion

Ring and ball. Most materials expand when heated. The ball will not pass through the ring until the ring is hotter than the ball. This means the ring has expanded to allow the ball to pass through.Ring and ball over flame
Light bulb, thermostat. The big light bulb heats a bi-metalic strip. When the strip bend enough, it breaks the circuit for the large bulb. When the strip cools and straightens, it turns on the large bulb again. A second view.Bimetallic strip completed contact to power lightbulb
Light bulb, thermostat, two bulbs. The big light bulb heats a bi-metalic strip. When the strip bend enough, it breaks the circuit for the large bulb and closes the circuit for the small bulb. When the strip cools and straightens, it switches off the small bulb and turns on the large bulb.Bimetallic strip between two contacts powering different bulbs
Convection Currents. A drop of food coloring is placed in water at the top of a glass loop. When one side is heated, a convection current is started and the food coloring will move around the ring.Heating one corner of a glass loop

Heat engines and the Second Law of Thermodynamics

Steam Engine. A boiler produces steam which is used to drive a piston. The piston, in turn, drives a wheel which drives an electromagnet, producing electricity. The light bulb will light up when enough electricity is produced.Steam engine powers light bulb
Drinking Duck. As the water evaporates from the outside of the head of the duck, the air pressure in the duck’s head drops. The liquid therefore rises up the duck’s body. When it rises enough, it tips it over, simultaneously breaking the liquid seal between the head and body, mixing the air in the two chambers, and getting the beak wet again. This is a heat engine driven by the temperature difference of the dry body and wet head.Glass drinking duck continually dips head in water
Thermoelectric Fan. The temperature difference between the water and the liquid nitrogen is used to create electricity and run the fan.Thermoelectric fan straddling two cups