Evaporation of water on duck's head cools vapor inside causing low pressure, etc.
How it works:
Dippy Duck is a small heat engine consisting of a hollow glass barbell with opposite ends able to seesaw about a knife edge pivot. One end of the barbell is...
Pure water cooled to below 273K without freezing; seeded to spontaneously crystallize.
What it shows:
A liquid can be taken to a temperature below its freezing point if it is cooled slowly and there are no nucleation sites for crystallization to begin. In...
Brass ball doesn't fit through brass ring until ring is heated.
What it shows:
Most solids (see Comments) expand when heated due to increased atomic and lattice vibrations. In this demo, a brass ring expands when heated to let a previously too small a ball...
Black body radiators in thermal equilibrium should emit the same spectrum of radiation; inside a muffle furnace at high temperature, objects should appear the same color, whatever their material.
A black body box is an idealized black body radiator. That is, any light emerging from the interior of the box is purely a product of the box’s temperature.
How it works:
As the light emerging from the cavity should be a product of the...
The thermal radiation emitted from a black body is temperature dependant. The tungsten filament of a bulb approximates a black body, and by increasing the current through the bulb, its temperature rises and so its color spectrum shifts to...
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...
James Clerk Maxwell postulated that since heat involves the movement of molecules, it might be possible to separate hot and cold air in a device with the help of a "friendly demon" who would sort out and separate the fast and slow moving...
