The origin of the thermometer
The first Clinical Digital Thermometer in 1593 by the Italian scientist Galileo (1564 - 1642) invented. His first exposure to only one end of the thermometer is a glass tube, the other side of the glass bulb with a large walnut. Give the glass bulb heat used, then the glass tube into the water. As the temperature of the glass tube in the water will move up and down, according to the number of moves you can determine the temperature and the temperature level.
Medical Thermometer has the role of thermal expansion and contraction so that the thermometer by the external atmospheric pressure and other environmental factors is high, measurement error.Later, Galileo's students and other scientists, on this basis, repeated improvements, such as the glass upside down, put the liquid on the tube, the tube being closed. The more prominent the French Bu Liao thermometer manufactured in 1659, he reduced the size of the glass bulb, and the temperature of material to mercury, such as thermometers already have a prototype of the thermometer now.
Thermometer hygrometer is used to measure the physical properties of the gas humidity analyzer. Humidity is the gas in the water vapor content, relative humidity, absolute humidity and two representations. Absolute humidity refers to the gas in the absolute content of water vapor, the most commonly used units of g / m ^ 3. In a certain temperature, pressure, per unit volume of water vapor content of a certain limit, known as the saturated water vapor content. Relative humidity refers to the absolute water vapor in the gas content and the same temperature, pressure, gas saturated with the volume ratio of water vapor content, commonly used symbols for the% RH.