Thermometers A thermometer is an instrument for measuring temperature.The most common scales are Fahrenheit and Celsius or Centigrade.Fahrenheit is used in the United States and some other English-speaking countries.On the Fahrenheit scale,the freezing point of water is 32F and its boiling point 212F.Celsius is used throughout most of the world.On the Celsius scale,the freezing point of water is 0c and its boiling point 100c Fahrenheit to Celsius:C=(F-32)5/9 Celsius to Fahrenheit:F=(F+32)9/5Thermometers A thermometer is an instrument for measuring temperature. The most common scales are Fahrenheit and Celsius or Centigrade. Fahrenheit is used in the United States and some other English-speaking countries. On the Fahrenheit scale, the freezing point of water is 32℉ and its boiling point 212℉. Celsius is used throughout most of the world. On the Celsius scale, the freezing point of water is 0℃ and its boiling point 100℃. • Fahrenheit to Celsius: C=(F-32)5/9 • Celsius to Fahrenheit: F=(F+32)9/5