De quoi est fait hygrometer
Measures air humidity.
- Human hair strand — a pour partie. The length changes with humidity.
- Gauge needle and dial — a pour partie. It shows the humidity.
- Spring — a pour partie. The tension of the hair.
- Wood — est fait de. Early hygrometers were a wooden frame with a sensitive fibre or hair.
- Plant fibre — est fait de. Humidity was shown by a fibre that changed length.