Who Invented the Hair Hygrometer?
Swiss inventor, physicist and geologist Horace Bénédict de Saussure invented the hair hygrometer in 1783. The hygrometer is an instrument used for measuring the amount of moisture content in the air. Does this Spark an idea?
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Function
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Hair strands contract and expands depending on the humidity of the air. At 0 percent, the hair contracts. However, at 100 percent, humidity hair is longest. A needle moves according to how much the hair expands, reporting the amount of relative humidity.
Types
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There are three types of hygrometers.
Saussure made the first hair hygrometer using a human hair.
The dry and wet-bulb psychometer is a type of hygrometer made up of two mercury thermometers. One thermometer is wrapped in wet cotton and the other one dry. Water evaporates form the wet bulb and absorbs heat. This causes the thermometer to drop. The difference in the two thermometers calculates how much moisture is in the air.
A third electronic hygrometer is produced by measuring the electrical current of lithium chloride in a series circuit.
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History
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Hair hygrometers were in regular use until the 1960s. Since hard to calibrate--and due to the invention of other hygrometers--they are not the most efficient to use since hard to calibrate.
Benefits
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A hair hygrometer is simple to make and can be produced at home.
Interesting Facts
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Before Saussure, Leonardo Da Vinci built the first version of the hair hygrometer in the 15th century.
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References
Resources
- Photo Credit (Les Alpinistes célèbres, Henry de Ségogne, Editions Mazenod 1956)
