Body temperature can be assessed using various devices and measured in Celsius or Fahrenheit.
Glass-bulb Thermometer:
Glass-bulb thermometers are hollow glass tubes with a bulb tip containing liquid such as ethanol or mercury. Historically, glass bulb mercury thermometers were the standard device to measure body temperature. Today, mercury thermometers are prohibited in many countries due to the hazardous effects of mercury and the risk of exposure if the glass bulb breaks. In general,...

Any physical property that depends consistently and reproducibly on temperature can be used as the basis of a thermometer. For example, volume increases with temperature for most substances. This property is the basis for the common alcohol thermometer and the original mercury thermometers. Other properties used to measure temperature include electrical resistance, color, and the emission of infrared radiation.
As many physical properties depend on temperature, the variety of thermometers is...

The definition of temperature in terms of molecular motion suggests that there should be a lowest possible temperature, where the average kinetic energy of molecules is zero (or the minimum allowed by quantum mechanics). Experiments confirm the existence of such a temperature, called absolute zero. An absolute temperature scale is one whose zero point is absolute zero. Such scales are convenient in science because several physical quantities, such as the volume of an ideal gas, are directly...

The body's temperature, measured in degrees, is determined by the balance between heat production and dissipation to the surrounding environment. For instance, if exercising vigorously, the body will produce more heat, causing sweat and dissipating that heat. Despite extreme environmental conditions and physical exertion, the human temperature-control system maintains a constant core body temperature (the temperature of deep tissues, which are the tissues located beneath the skin and other...

Body temperature reflects the equilibrium between heat production and heat loss within the body. Most heat is generated by metabolically active tissues, particularly the liver, heart, brain, kidneys, and endocrine organs. At rest, skeletal muscles contribute 20–30% of total heat production, but during vigorous exercise, this can increase up to 30–40 times.
The average body temperature is approximately 37°C (98.6°F) and typically ranges from 36.1–37.2°C (97–99°F), remaining relatively stable...

Heat and temperature are essential concepts for everyone every day. The study of heat and temperature is part of an area of physics known as thermodynamics. It is not always easy to distinguish heat and temperature.
The concept of temperature has evolved from the common concepts of hot and cold. The scientific definition of temperature explains more than just our sense of hot and cold. Temperature is operationally defined as the quantity measured with a thermometer. Furthermore, temperature is...