degrees Celsius (C) to Kelvins (K) conversion

What is degrees celsius?

Let's explore the world of degrees Celsius, a fundamental unit of temperature measurement. This explanation will cover its definition, history, conversion formulas, and real-world applications.

Definition of Degrees Celsius

The degree Celsius ($^\circ C$) is a unit of temperature on the Celsius scale, a temperature scale originally designed so that the freezing point of water was $0 ^\circ C$ and the boiling point was $100 ^\circ C$ at standard atmospheric pressure. It is an SI derived unit.

History of the Celsius Scale

The Celsius scale was invented by Swedish astronomer Anders Celsius in 1742. Originally, Celsius defined his scale "upside down": zero represented the boiling point of water, and 100 represented the freezing point. It was later reversed to its current form by either Jean-Pierre Christin in 1743 or Carolus Linnaeus in 1744.

Conversion Formulas

Here are the key formulas to convert Celsius to other common temperature scales:

• Celsius to Fahrenheit:

  $$^\circ F = \left(^\circ C \times \frac{9}{5}\right) + 32$$

• Celsius to Kelvin:

  $$K = ^\circ C + 273.15$$

• Fahrenheit to Celsius:

  $$^\circ C = \frac{5}{9}(^\circ F - 32)$$

Celsius and Thermodynamics

Celsius plays a key role in thermodynamics. The absolute zero temperature (0 Kelvin), where all molecular motion ceases, is equivalent to -273.15 $^\circ C$.

Real-World Examples

• Body Temperature: Normal human body temperature is approximately 37 $^\circ C$.
• Room Temperature: Comfortable room temperature is often around 22-25 $^\circ C$.
• Cooking: Water boils at 100 $^\circ C$ at sea level, crucial for cooking and sterilization.
• Weather: Daily temperatures are commonly reported in Celsius in many parts of the world. For instance, a pleasant summer day might be 28 $^\circ C$.
• Freezing Point: Water freezes at 0 $^\circ C$.

Interesting Facts

• The Celsius scale is widely used around the world, especially in scientific contexts.
• The size of one degree Celsius is the same as the size of one Kelvin. Only the zero point is different.

Notable Associations

• Anders Celsius: The Swedish astronomer who originally devised the scale. His work laid the foundation for a standardized temperature measurement system.

For further reading, you might find the NIST Temperature Scale FAQ helpful.

What is Kelvins?

Kelvin is the base unit of temperature in the International System of Units (SI), commonly used in scientific and engineering fields. It's an absolute thermodynamic temperature scale, meaning its zero point is absolute zero, the point at which all molecular motion ceases.

Definition of Kelvin

The Kelvin scale is defined by setting the triple point of water (the temperature at which water can exist in equilibrium as a solid, liquid, and gas) to exactly 273.16 K. A temperature difference of 1 Kelvin is the same as a temperature difference of 1 degree Celsius. The symbol for Kelvin is K (no degree symbol).

The Formation of the Kelvin Scale and Lord Kelvin

The Kelvin scale is named after William Thomson, 1st Baron Kelvin (1824–1907), a British physicist who proposed the absolute thermodynamic temperature scale. He recognized the need for a temperature scale with an absolute zero point, independent of the properties of any particular substance. The concept of absolute zero arises from extrapolating the behavior of gases as they cool.

Lord Kelvin contributed significantly to thermodynamics, electromagnetism, and other areas of physics. He formulated the second law of thermodynamics and played a key role in the development of the transatlantic telegraph cable.

Converting to and from Kelvin

Here are the formulas to convert between Kelvin and other common temperature scales:

• Celsius to Kelvin: $K =$^\circ C + 273.15$
• Fahrenheit to Kelvin: $K = (^\circ F - 32) \times \frac{5}{9} + 273.15$

Interesting Facts About Kelvin

• Absolute Zero: Absolute zero (0 K or -273.15 °C) is theoretically the lowest possible temperature. In practice, it's impossible to reach absolute zero perfectly, although scientists have come incredibly close.
• No Negative Values: Unlike Celsius or Fahrenheit, the Kelvin scale does not have negative values. This is because it starts at absolute zero, the lowest possible temperature.

Real-World Examples of Kelvin Temperatures

• Space: The average temperature of the cosmic microwave background radiation (the afterglow of the Big Bang) is about 2.7 K.

• Cryogenics: Liquid helium, used in cryogenics for cooling superconducting magnets in MRI machines, has a boiling point of approximately 4.2 K.

• Light Bulbs: The surface of the sun is about 5,778K. Standard incandescent light bulbs operate at temperatures of 2,500-3,000 K. This can be measured using principles of blackbody radiation and Wien's displacement law to see how the peak wavelength is inversely proportional to temperature:

  $\lambda_{max} = \frac{b}{T}$

  where $b$ is Wien's displacement constant ($2.898 \times 10^{-3} m \cdot K$) and $T$ is the temperature in Kelvin.

• Material Science: The melting point of various materials is often expressed in Kelvin. For example, the melting point of copper is 1357.77 K.

• Scientific Research: Kelvin is extensively used in scientific research, especially in fields like physics, chemistry, and materials science, where precise temperature measurements are essential.