It works on the principle of heat
and thermistor plays a key role in it
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Geysers are temporary geological features. Geysers are generally associated with volcanic areas. As the water boils, the resulting pressure forces a superheated column of steam and water to the surface through the geyser's internal plumbing. The formation of geysers specifically requires the combination of three geologic conditions that are usually found in volcanic terrain.Intense heat The heat needed for geyser formation comes from magma that needs to be near the surface of the earth. The fact that geysers need heat much higher than normally found near the earth's surface is the reason they are associated with volcanoes or volcanic areas. The pressures encountered at the areas where the water is heated makes the boiling point of the water much higher than at normal atmospheric pressures.WaterThe water that is ejected from a geyser must travel underground through deep, pressurized fissures in the Earth's crust.A plumbing systemIn order for the heated water to form a geyser, a plumbing system is required. This includes a reservoir to hold the water while it is being heated.

Geysers are generally aligned along faults. The plumbing system is made up of a system of fractures, fissures, porous spaces and sometimes cavities. Constrictions in the system are essential to the building up of pressure before an eruption.
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