How to Make a Hygrometer With Strands of Hair
More elaborate types of hygrometers exist to measure humidity, but you can make a basic hygrometer out of a few household items and a human hair. As many people can tell you from personal experience, hair responds to moisture in the air, expanding as moisture increases and contracting as moisture decreases. Hair hygrometers take advantage of that fact to provide rough measures of humidity in the air. Does this Spark an idea?
Things You'll Need
- 9-by-4-inch block of wood
- 3-by-3-inch piece of plastic thin enough to cut with scissors
- 3 human hairs at least 8 inches long
- Dime
- 2 nails
- Tape
- Glue
- Scissors
Instructions
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1
Prepare the triangle. Using scissors, cut the 3-by-3-inch piece of plastic into a thin, long isosceles triangle. The triangle's thin tip will serve as the pointer of your measurement device.
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2
Affix the dime, one nail and the hairs to the triangle. Tape the dime to the top point of the triangle, and poke one of the nails through the bottom of the triangle. Jiggle the triangle so it can move around the nail. Glue one end of the three human hairs to the middle of the triangle.
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3
Attach the triangle to the wood using the nail. The triangle should be about a quarter of the way up from the bottom of the wood, whose longer side will run perpendicular to the ground. The triangle's long side will be perpendicular to the wood block's long side. Make sure the triangle can still move freely.
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4
Hammer the second nail into the wood about an inch from the top, directly above where the hairs are attached to the triangle. Glue the top ends of the hair to this nail, making sure the hairs are taut and trimming off any excess hair after you are done gluing. The length of the hair and the length of the wood should be parallel; the triangle will be perpendicular to these.
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5
Once the glue dries, your human hair hygrometer can be used to measure humidity.
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Tips & Warnings
When the pointer points down, the hair has expanded and the air is more humid. When the pointer points up, the hair has contracted and the air has less moisture.
