You will need to include the surroundings as part of the system. A Celsius degree is sometimes also called Centigrade. It was used in some fields of technology in USA, but NIST does not recommend the use of Rankine anymore. The abbreviation “cgs” comes from words “centimetre-gram-second”. . Celsius uses the unit "degrees" and is abbreviated as °C. Does the temperature of a body depend on its size? On the Reaumur temperature scale, the freezing point of water is 0ºR and the boiling temperature is 80ºR. (b) At a higher temperature, this strip bends to the right, because the metal on the left has expanded more than the metal on the right. The instrument used to measure temperature is a thermometer. Absolute zero is the temperature at which there is no molecular motion. Figure 1. Temperature scales may be relative or absolute. No, the system can be divided into smaller parts each of which is at the same temperature. The International System of Units (SI) unit of temperature is the Kelvin (K), although other temperature scales are more commonly used for everyday situations. In comparison, the coldest recorded place on Earth’s surface is Vostok, Antarctica at 183 K (–89ºC), and the coldest place (outside the lab) known in the universe is the Boomerang Nebula, with a temperature of 1 K. Figure 6. Relative scales are degree scales. So we need more specific way to indicate temperature. A temperature scale can be created by identifying two easily reproducible temperatures. Thermodynamic temperature is very difficult to measure and several international temperature scales for practical measurements have been published: Some additional scales have also been used, for example PLTS-2000 for improved measurements of very low temperatures in the range 0.9 mK...1 K (Provisional Low Temperature Scale of 2000). Temperature is a different quantity from the total amount of thermal energy in a substance, which is dependent on the size of the object. The temperature of the human body is about 98 °F on the revised scale. Any physical property that depends on temperature, and whose response to temperature is reproducible, can be used as the basis of a thermometer. Three of the most common are Kelvin, Celsius, and Fahrenheit. If you add boiling water to a cup at room temperature, what would you expect the final equilibrium temperature of the unit to be? The freezing point of water equals 491.67 °Rankine. (a) Suppose a cold front blows into your locale and drops the temperature by 40.0 Fahrenheit degrees. Temperature may be described using the Zeroth Law of Thermodynamics and the kinetic theory of gases. The scientific definition of temperature is less ambiguous than your senses of hot and cold. Temperature is the property of matter which reflects the quantity of energy of motion of the component particles. • Note that all of the graphs extrapolate to zero pressure at the same temperature. And since different scales have been used in different parts of the world, there are still several different scales in use. To convert from ºC to K, use the equation. Figure 5. .The circuit diagram shows the set-up for measurement of emf generated in a thermocouple connected between points X and Y. What are these temperatures on the Celsius scale? Note that zero on a logarithmic scale would occur off the bottom of the page at infinity. Rankine scale was presented by a Scottish William Rankine in 1859, so a few years after Kelvin scale. Celsius is currently a derived unit for temperature in the SI system, kelvin being the base unit. It is a comparative measure of how hot or cold a material is. Temperature Scales There are three main temperature scales that are used today: Celsius, Fahrenheit, and Kelvin. That is, heat will flow from the hotter object to the cooler one until they have exactly the same temperature. Temperature is independent of the size or quantity of an object. temperature: the quantity measured by a thermometer, Celsius scale: temperature scale in which the freezing point of water is 0ºC and the boiling point of water is 100ºC, degree Celsius: unit on the Celsius temperature scale, Fahrenheit scale: temperature scale in which the freezing point of water is 32ºF and the boiling point of water is 212ºF, degree Fahrenheit: unit on the Fahrenheit temperature scale, Kelvin scale: temperature scale in which 0 K is the lowest possible temperature, representing absolute zero, absolute zero: the lowest possible temperature; the temperature at which all molecular motion ceases, thermal equilibrium: the condition in which heat no longer flows between two objects that are in contact; the two objects have the same temperature, zeroth law of thermodynamics: law that states that if two objects are in thermal equilibrium, and a third object is in thermal equilibrium with one of those objects, it is also in thermal equilibrium with the other object, [latex]\begin{array}{lll}\Delta T\left(^{\circ}\text{F}\right)& =& {T}_{2}\left(^{\circ}\text{F}\right)-{T}_{1}\left(^{\circ}\text{F}\right)\\ & =& \frac{9}{5}{T}_{2}\left(^{\circ}\text{C}\right)+\text{32}\text{.}0^{\circ}-\left(\frac{9}{5}{T}_{1}\left(^{\circ}\text{C}\right)+\text{32}\text{.