Kelvin

Definition

Kelvin is the base unit of temperature in the International System of Units (SI), named after the British mathematician and physicist William Thomson, 1st Baron Kelvin. It is one of the seven base units in the SI system and is used to measure the absolute temperature of a system, providing a scale that is directly related to the fundamental properties of matter and energy.

5 Must Know Facts For Your Next Test

1. The Kelvin scale is an absolute temperature scale, where 0 Kelvin represents the lowest possible temperature, known as absolute zero.
2. One Kelvin is defined as the fraction 1/273.16 of the thermodynamic temperature of the triple point of water, which is the temperature at which the solid, liquid, and gaseous phases of water coexist in equilibrium.
3. The Kelvin scale is used in scientific and technical fields, as it is directly related to the fundamental properties of matter and energy, making it the preferred scale for scientific measurements and calculations.
4. The Kelvin scale is directly proportional to the average kinetic energy of the particles in a system, with higher temperatures corresponding to higher kinetic energy.
5. The Kelvin scale is the only temperature scale where the unit interval is the same size as the Celsius degree, but the zero point is set at absolute zero, the lowest possible temperature.

Review Questions

• Explain the relationship between the Kelvin scale and the Celsius scale, and how they are used in scientific and everyday applications.
  • The Kelvin scale and the Celsius scale are both temperature scales, but they differ in their zero points and the size of their units. The Kelvin scale is an absolute temperature scale, where 0 Kelvin represents the lowest possible temperature, known as absolute zero. In contrast, the Celsius scale defines the freezing point of water as 0 degrees and the boiling point of water as 100 degrees at standard atmospheric pressure. The Kelvin scale is the preferred scale for scientific and technical applications, as it is directly related to the fundamental properties of matter and energy. However, the Celsius scale is more commonly used for everyday temperature measurements, as it provides a more intuitive scale for human experience.
• Describe the significance of the triple point of water in the definition of the Kelvin scale, and explain how this relates to the measurement of absolute temperature.
  • The triple point of water, which is the temperature at which the solid, liquid, and gaseous phases of water coexist in equilibrium, plays a crucial role in the definition of the Kelvin scale. One Kelvin is defined as the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. This definition is significant because the triple point of water is a well-defined and reproducible physical state, making it an ideal reference point for the measurement of absolute temperature. The Kelvin scale is directly proportional to the average kinetic energy of the particles in a system, with higher temperatures corresponding to higher kinetic energy. This relationship between temperature and the fundamental properties of matter and energy is what makes the Kelvin scale the preferred scale for scientific measurements and calculations.
• Analyze the importance of the Kelvin scale in scientific research and technological applications, and explain how its use contributes to the advancement of our understanding of the physical world.
  • The Kelvin scale is essential in scientific research and technological applications because it is directly related to the fundamental properties of matter and energy. By using the Kelvin scale, scientists and engineers can make precise measurements and calculations that are essential for advancing our understanding of the physical world. For example, the Kelvin scale is crucial in fields like thermodynamics, where the relationships between temperature, energy, and the behavior of systems are studied. It is also essential in cryogenics, where the properties of materials at extremely low temperatures are investigated. Additionally, the Kelvin scale is used in the development of advanced technologies, such as superconductors and quantum computing, where precise temperature control is crucial. By providing a standardized and absolute scale for temperature measurement, the Kelvin scale has enabled significant progress in scientific research and technological innovation, ultimately contributing to our deeper understanding of the universe and the laws that govern it.

Related terms

Celsius: The Celsius scale is a temperature scale that defines the freezing point of water as 0 degrees and the boiling point of water as 100 degrees at standard atmospheric pressure. It is commonly used for everyday temperature measurements.

Fahrenheit: The Fahrenheit scale is a temperature scale that defines the freezing point of water as 32 degrees and the boiling point of water as 212 degrees at standard atmospheric pressure. It is commonly used in the United States for everyday temperature measurements.

Absolute Zero: Absolute zero is the lowest possible temperature, where the motion of atoms and molecules reaches its minimum. It is defined as 0 Kelvin, which is equivalent to -273.15 degrees Celsius or -459.67 degrees Fahrenheit.