How Do You Make A Simple Hygrometer?
A hygrometer is an instrument used to measure humidity, the amount of water vapor in the air. The earliest form, the mechanical hygrometer, was invented in 1783 by Horace Bénédict de Saussure, using human hair to determine the moisture content of the air. Modern forms include the dual-thermometer psychrometer, used to measure relative humidity, and the chilled mirror hygrometer, used to measure dewpoint. These instructions are for a mechanical hygrometer. Cut the plastic into the shape of an isosceles triangle to form a pointer. Tape a dime to the apex of the triangle. Poke a nail through the pointer near the base of the triangle and wiggle it so that the pointer moves freely around the nail. Glue the hair strands to the plastic between the dime and the nail hole so they run parallel to the base of the triangle. Position the pointer on the wood or Styrofoam base three-quarters down from the top edge. Attach the nail running through the pointer to the base. Drive the nail far enough in
