What is Temperature – Measure of Hot or Cold?

Is it too cold or too hot today? Why did you turn on the air conditioner? These are the normally asked questions in our day to day life. The degree of hotness or coldness is measured by temperature. When a person is ill or has a fever specifically, a medical practitioner particularly examines the degree of temperature that is reflected on the thermometer. Temperature plays a vital role in measuring the hotness or coldness.

In this article, let us know the temperature definition and how it is measured in detail.

Know About Temperature

Temperature is the measure of how hot or cold the substance is. It is the physical quantity which is the manifestation of thermal energy present in the body or substance. Temperature is the representation of the energy flow or transfer and also indicates the source of occurrence of heat.

When a hot object comes in contact with another object, the heat from the hot body is transferred to another body. Even when a cold object comes in contact with another object, the chillness is transferred from one object to another. In this process temperature transfer takes place.

Temperature is usually measured using a thermometer or calorimeter and the temperature is measured in the Fahrenheit scale (°F), Celsius scale (°C), and the Kelvin scale (K). Absolute zero is the lowest temperature that is theoretically recorded. The temperature depends only on the quantity of matter. Since hot and cold are generalized to measure the heat and chillness. It was necessary to measure the temperature of the object to know the exact value. Hence the thermometer was invented in the 18th century.

Temperature Measuring Aid – The Thermometer

To know the accurate temperature of the body or object, thermometers were invented. A thermometer is a device that measures the temperature gradient, specifically the degree of hotness or coldness of an object. The first thermometer was discovered by Santorio Santorio. Later in the 17th and 18th-century developments and standardization were made on the thermometer by Daniel Gabriel Fahrenheit.

Daniel Gabriel Fahrenheit discovered mercury-in-glass thermometer and Fahrenheit scale. There are many types of thermometer available for measuring temperature for various purposes and medical diagnosis. Following are the types of thermometers widely used.

  • Medical thermometer or Clinical thermometer
  • Digital thermometer
  • Laboratory thermometer
  • Mercury thermometer
  • Infrared ear thermometer
  • Strip thermometer
  • Alcohol in glass thermometer
  • Constant volume thermometer
  • Constant pressure gas thermometer
  • Platinum resistance thermometer
  • Thermocouple thermometer
  • Pyrometer thermometer

The clinical thermometer is as shown in the figure below. It is specifically used to measure the human body temperature. It features a narrow glass tube with a bulb containing mercury at the end. Clinical thermometers give accurate value and are used in medical fields in hospitals and clinics. Clinical thermometers have been replaced by digital thermometers in recent days.

The digital thermometer is the most accurate and fastest type of thermometer. Temperature is usually measured by holding the digital thermometer under the armpit or on the body. This device can also be used to measure temperature orally by keeping the tip of the device inside the mouth.

Infrared ear thermometers are used to measure the temperature in less than a second using infrared rays. Infrared ear thermometers are less accurate since they show incorrect values when the wax is present in the ear.

Strip-type thermometers are used on the forehead to measure the body temperature and are comparatively less accurate. It is used on infants and small children.

These are some of the types of thermometers that are available. Hope you have understood the temperature definition and types of thermometers.