Summarizing Temperature

Summary

• Temperature is the quantity measured by a thermometer.
• Temperature is related to the average kinetic energy of atoms and molecules in a system.
• Absolute zero is the temperature at which there is no molecular motion.
• There are three main temperature scales: Celsius, Fahrenheit, and Kelvin.
• Temperatures on one scale can be converted to temperatures on another scale using the following equations:

  \({T}_{\text{º}\text{F}}=\cfrac{9}{5}{T}_{\text{º}\text{C}}+\text{32}\)

  \({T}_{\text{º}\text{C}}=\cfrac{5}{9}({T}_{\text{º}\text{F}}-\text{32})\)

  \({T}_{\text{K}}={T}_{\text{º}\text{C}}+\text{273}\text{.}\text{15}\)

  \({T}_{\text{º}\text{C}}={T}_{\text{K}}-\text{273}\text{.}\text{15}\)

• Systems are in thermal equilibrium when they have the same temperature.
• Thermal equilibrium occurs when two bodies are in contact with each other and can freely exchange energy.
• The zeroth law of thermodynamics states that when two systems, A and B, are in thermal equilibrium with each other, and B is in thermal equilibrium with a third system, C, then A is also in thermal equilibrium with C.

Glossary

temperature

the quantity measured by a thermometer

Celsius scale

temperature scale in which the freezing point of water is \(0\text{º}\text{C}\) and the boiling point of water is \(\text{100}\text{º}\text{C}\)

degree Celsius

unit on the Celsius temperature scale

Fahrenheit scale

temperature scale in which the freezing point of water is \(\text{32}\text{º}\text{F}\) and the boiling point of water is \(\text{212}\text{º}\text{F}\)

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