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How it Works
Theheat engine uses a principle of magnetism discovered by Pierre Curie. He studied the effects of temperature on magnetism. Ferromagnetism covers the field of normal magnetism that people typicallyassociate with magnets. All normal magnets and the material that are attracted to magnets are ferromagnetic materials. Pierre Curie discovered that ferromagnetic materials have a critical temperature atwhich the material loses their ferromagnetic behavior. This is known as its Curie Point. As an example, a piece of iron (Fe) at room Figure 1 temperature is strongly attracted to a magnet. Heat theiron to a temperature of 770 C, which is its Curie Point, it loses its ferromagnetism behavior and it is no longer be attracted to a magnet. If we let the iron cool, it regains its ferromagneticbehavior and is attracted to the magnet again. We can use this property to construct a small swinger type heat engine. The heat engine uses a nickel alloy wire that has a low Curie Point, see drawing toright. When the wire is at room temperature it is attracted to the magnet, and swings close to the magnet. In this position, labeled B
in the drawing, it is heated by the flame of a smallbirthday cake candle. When the material temperature reaches its Curie Point, it loses it ferromagnetism and falls away from the magnet, to position A, and out of the candle flame. As the wire cools itregains its ferromagnetism and is attracted to the magnet again, where it swings back up toward the magnet to position B and back into the candle flame. This process repeats, swinging the nickel allow wireback and forth.
Figure 2 Figure 2 illustrates the components and alignment of the magnet in relationship to the candle wick (shown as flame) and 1.5” aluminum wire and ring terminal.