The Thermometer was invented by Italian scientist Galileo in 1600. It is the combination of two words "Thermo" which means heat and "meter" which means to measure. It is a glass sealed tube which has mercury or alcohol at its bottom. The volume of mercury or alcohol rises along with rise in temperature of the subject/object. The hotter the temperature, the higher the mercury/alcohol will rise. There are different types of thermometer depending of its usages; some of them are listed below:
Clinical Thermometers: Measure the body temperature of the patient
Ear (Tympanic) Thermometers: It is located near the brain to measure the body temperature
Pacifier Thermometers: Check the body temperature of babies or infants
Underarm or Oral Thermometers: Kept underarms to measure the body temperature
Outdoor Thermometers: Measure the temperature of the surrounding air