Temperature
Temperature is defined as an indicator of the amount of thermal energy stored within an object. It also reflects the extent of atomic movement, which can be expressed mathematically to illustrate the relationship between the kinetic energy of molecules in a substance and its temperature.
Heat is the measure used to assess the warmth or coolness of a substance, playing a vital role in determining the natural direction of heat transfer. Various units are used to measure temperature, including:
- Kelvin: This scale is based on absolute zero and illustrates the relationship between absolute zero and the Celsius scale, with absolute zero being approximately 273.15 degrees Celsius.
- Celsius: Denoted as °C, it is the primary and internationally recognized scale for everyday temperature measurement.
- Fahrenheit: Represented by °F, this scale is officially used in the United States for measuring temperature.
Temperature Measurement Devices
Thermometer
Commonly referred to as a clinical thermometer or simply a thermometer, this compact device is designed to measure the temperatures of materials in various states—gas, liquid, or solid. In medical settings, thermometers are frequently utilized to monitor a patient’s body temperature and health condition. They can also be employed outdoors to measure ambient temperatures when placed near windows or doors.
Inverted Thermometer
This mercury thermometer is specifically designed to measure water temperatures at various depths and has been used by scientists from 1900 to 1970.
Pyrometer
Also known as a radiation thermometer or heat density gauge, this instrument measures the heat density emitted from a thermal source and its cooling effects on surrounding objects. It typically functions as a differential thermometer, featuring a bulb coated with silver or gold, and is also used to ascertain the temperature of furnaces or melts.
Humidity
The term humidity refers to the quantity of moisture present in an object, regardless of its state—gas or solid. It is commonly used to describe the level of water within a substance, and humidity can be categorized into various forms, including atmospheric humidity and soil moisture. Ultimately, it relates to the moisture content irrespective of the medium.
Devices for Measuring Temperature and Humidity
Hygrometer
This device consists of two thermometers: one is a standard dry thermometer, while the other, known as the wet-bulb thermometer, has its wick in a small reservoir of distilled water, allowing it to measure humidity levels effectively.
Hygrograph
The hygrograph is an instrument that includes a strand of human hair, fixed at one end to a mechanism connected to an indicator arm, which points to a revolving cylinder that holds a paper chart for recording relative humidity. When the humidity in the air increases, the hair strand stretches.