As accurate as laboratory thermometers. Predict changes in the weather by referencing fluid rise and fall in the barometric tube. The hygrometer measures humidity. When the temperature goes up, the clear fluid becomes less dense and rises - forcing the spheres down one by one. When the temperature goes down, the clear fluid becomes denser - forcing the spheres upward.
Humidity is determined by reading the number at the end of the indicator pointer.
This fascinating weather instrument provides a reading of the current weather conditions using several scientific methods established hundreds of years ago. Our thermometer is a replica based on Galileo's experiments. When the temperature rises, the liquid in the glass cylinder becomes less dense and the spheres sink slowly, one by one. Conversely, the spheres will rise as the temperature decreases. The lowest floating sphere in the upper portion of the cylinder indicates the correct temperature.