Thermometer

The thermometer is a device that measures temperature or temperature gradient using a variety of different principles;it comes from the Greek roots thermo,heat,and meter,to measure.A thermometer has two important elements:the temperature sensor(e.g. the bulb on a mercury thermometer)in which some physical change occurs with temperature, plus some means of converting this physical change into a value(e.g.the scale on a mercury thermometer).Industrial thermometers commonly use electronic means to provide a digital display or input to a computer.