A thermometer is a device used to measure temperature. It consists of a long, narrow, uniform glass tube with a bulb at one end. The bulb is filled with a liquid (usually mercury or colored alcohol) that expands and contracts with changes in temperature, causing the level of the liquid in the tube to rise or fall. The temperature can then be read from a scale marked on the tube.
Types of Thermometers
Mercury Thermometer: Uses mercury as the liquid, but due to its toxic nature, it is being phased out in many places.
Digital Thermometer: Uses electronic sensors to measure temperature and displays the results on a digital screen.
Infrared Thermometer: Measures temperature from a distance by detecting the infrared energy emitted by an object.
How to Use a Thermometer
Shake the thermometer to ensure the liquid is below the highest temperature recorded.
Place the thermometer in the area to be measured and wait for the liquid to rise and stabilize.