P4.01-3 Meteorological instruments: temperature, humidity and evaporation Temperature and humidity are two important meteorologic parameters. They have a great influence on numerous processes in nature, such as the evaporation rate of water, germination of seeds and the spread of (plant) diseases. 16.34 Digital thermometer The thermometer can be used to measure temperature in degrees Celsius and Fahrenheit and has a measuring range of -50 tot +150°C.  Accuracy is 0.5°C. The display can be read to 0.1 °C. The thermometer has options to display the measurement and to reset the maximum- and minimum temperature and hold facility. The instrument can also be used to measure temperature in ensilage, hay, peat or other soft materials or liquids. 16.42 Assmann psychrometer Model in chromed design. The model is equipped with two thermometers and a psychrometer with a measuring range of -10 to +60 °C. The psychrometer is fitted with a mechanical ventilator. Accuracy of both thermometers +/- 0.2 °C. Division 0.2 °C. 16.45 Portable relative humidity and temperature meter The portable digital relative humidity and temperature meter displays directly relative humidity or temperature. 16.46.Q Thermo-hygrograph This instrument independently measures and records the relative humidity and the temperature of the surroundings. 16.85 Piche evaporation meter The instrument only indicates the evaporation rate. Suitable for educational purposes. 16.93 Sunshine recorder Sunshine recorder according to Campbell-Stokes for the registration of the number of hours of sunshine per day. 16.89 Evaporation pan The class-A evaporation pan is used to determine the evaporation rate of open water. For a more exact use of the evaporation pan it is recommended to use an additional wind path meter. For automatic measurement of the evaporation use can be made of a level sensor. Weather stations