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Relation Between Celsius and Kelvin

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Introduction to Celsius and Kelvin

You must have felt your temperature due to fever during times of illness. During the Covid-19 times, everywhere we visited, our temperatures would be checked. As per the Georgia State University, temperature can be defined as a measure which is the average of kinetic energy of a substance. This temperature is measured using certain scales universally. Today we will study two of them - celsius and kelvin. 

Celsius and Kelvin Scales

Kelvin and Celsius are standard units that are used to measure temperature. They have both similarities and differences. One difference is that their starting point varies. IF K is the temperature on the Kelvin Scale and D is the temperature on the Celsius scale, then 

K = D + 273 or D = K - 273. 


The units for Celsius and Kelvin are degree celsius and the temperature in the kelvin scale itself respectively. 


The scales are used to obtain measurements of temperature which are then used in various calculations and calibrations. The facts and parameters for both celsius and kelvin are equally valid. The value of Kelvin especially stands at -273 which is also the negative reciprocal of 0.0366. It is considered as a reliable thermodynamic measuring scale and because it gives almost errorless results, it is widely used by scientists. While celsius is more familiar to common people, kelvin is used in standardized processes and equations. 


With international agreements certifying the celsius scale, we can use it to measure both the absolute zero and triple point apart from the freezing and boiling points of water. 

Difference Between Celsius and Kelvin Scale

Until 1954, Scientists stated that the melting point of ice is 00 C and the boiling point of ice is 100 0C. All these parameters are considered under constant temperature and pressure. It would help if you learnt all these from your schools.

 

Well, the unit' degrees Celsius' is available in the standard Celsius scale. The international agreement has certified this scale. You can calculate the temperature of two different points, such as absolute zero and absolute point. This type of scale is used to calculate the temperature difference of specially prepared water.

 

Temperature measuring units like Celsius and Kelvin both are significant. The use of these two units in particular in the scientific world. In these cases, calibration is essential. Also, these two units possess very much similarity along with distinct quality.

 

These two parameters are widely used among multiple sectors for the proper measurement of instruments. 

Insights from History:

Andres Celsius Put forward the unit 'Celsius" after his name. He invented the unit in 1742. Just explained before, the boiling point and melting point of ice before 1954 was 1000C and 0oC. These parameters were obtained under standard atmospheric pressure.

 

Scientists considered the obtained measurements for the calculation of multiple problems and any other important calculations or mechanical usages.

 

However, the actual value is -273.15 0C, and the triple point lies at 00C. Many scientists consider the definition for Celsius scale still worthy. Well, let's not focus on the definition but focus on facts and parameters.

 

Like Celsius, Kelvin was denoted as the degree unit to honor Sir William Thomson the Baron of Kelvin. He was the first person who proposed that there should be another system just like the same size as the unit (Celsius). 

 

Some scientists are predicting the reason behind why it can easily be combined with any type of mathematical equation. Also, the definition has the statement that it is having variables of temperature. 

Calculation of Celsius and Kelvin

The Celsius scale slightly differs from the Kelvin but not that much. First, you may change it to Kelvin. Then the value is ready to apply.  

 

It is quite easy if you consider the conversion as usual. If you want to convert it to Kelvin, add 273.15 to your Celsius value, such as K = °C + 273.15.

 

But in the case of calculation of Celsius, try the subtraction method.

 

Subtract the same constant from Kelvin value to convert it to Celsius such as °C = K − 273.15.

FAQs on Relation Between Celsius and Kelvin

1. What is the fundamental relationship between the Celsius and Kelvin temperature scales?

The fundamental relationship is that both Celsius and Kelvin scales measure temperature using the same interval size, but they have different starting points. A change of one degree on the Celsius scale is exactly equal to a one-unit change on the Kelvin scale. The key difference is that the Kelvin scale begins at absolute zero, while the Celsius scale sets its zero point at the freezing point of water.

2. What is the formula to convert a temperature from Celsius (°C) to Kelvin (K)?

The official formula to convert a temperature from degrees Celsius to Kelvin is: K = °C + 273.15. To find the Kelvin value, you simply add 273.15 to the given Celsius temperature. For many school-level and general calculations, this is often rounded to K = °C + 273.

3. How do the Celsius and Kelvin scales differ in their zero points?

The primary difference between the two scales lies in their defined zero points, which gives them different frames of reference:

  • The Celsius scale sets 0°C as the freezing point of water at standard atmospheric pressure. It is a relative scale based on a common physical property.
  • The Kelvin scale sets 0 K as absolute zero. This is the theoretical temperature where all thermal motion of particles ceases, making it an absolute scale. Absolute zero corresponds to -273.15°C.

4. Why is the number 273.15 used for converting between Celsius and Kelvin?

The number 273.15 is the precise value that links the zero point of the Celsius scale to the zero point of the Kelvin scale. Scientists have determined that absolute zero (0 K) is equivalent to -273.15°C. Therefore, to align the two scales, this value must be added to a Celsius reading to find its equivalent on the absolute Kelvin scale. For example, the freezing point of water is 0°C, which is 273.15 K.

5. Why is a temperature change of 1°C equivalent to a change of 1 K?

A temperature change of 1°C is equivalent to a change of 1 K because both scales were designed with the same magnitude of division. This was based on the properties of water, where the interval between its freezing and boiling points is divided into 100 units. On the Celsius scale, this range is 0°C to 100°C. On the Kelvin scale, this same range corresponds to 273.15 K to 373.15 K. Since the interval is 100 units on both scales, a one-unit change represents the same temperature difference.

6. Why is the Kelvin scale preferred over Celsius in scientific calculations and laws?

The Kelvin scale is preferred in scientific fields like physics and chemistry because it is an absolute thermodynamic scale. Its zero point (0 K) represents a true physical minimum—the complete absence of thermal energy. This makes temperature values on the Kelvin scale directly proportional to the kinetic energy of particles. Many fundamental scientific laws, such as the Ideal Gas Law (PV=nRT), require an absolute temperature to function correctly and avoid mathematical inconsistencies that would arise from using negative Celsius values.

7. Can a temperature have a negative value on the Kelvin scale?

No, a temperature cannot have a negative value on the Kelvin scale. The zero point of this scale, 0 K, is defined as absolute zero. This is the lowest possible temperature that can theoretically exist in the universe, where all classical motion of particles stops. Since there is no state colder than absolute zero, there are no negative values on the Kelvin scale.

8. What are some real-world examples where the Celsius scale is used?

The Celsius scale is practical for everyday life because its reference points are easy to relate to human experience. Common real-world examples include:

  • Weather forecasts: Most countries use °C to report air temperature.
  • Cooking: Oven temperatures and food preparation guides often use Celsius.
  • Medicine: Clinical thermometers measure body temperature in °C.
  • Domestic appliances: Refrigerators, freezers, and air conditioners are set in Celsius.

9. Why is Kelvin not expressed in 'degrees' like Celsius?

Kelvin is not expressed in 'degrees' because it is an absolute scale that directly measures thermodynamic temperature. According to the International System of Units (SI), the kelvin (symbol K) is a fundamental unit of measurement, similar to the metre for length or the second for time. The term 'degree' is used for relative scales like Celsius and Fahrenheit, which measure temperature relative to arbitrary reference points (e.g., the freezing point of water), rather than an absolute zero.

10. How do Celsius and Kelvin relate to the Fahrenheit scale?

The Celsius, Kelvin, and Fahrenheit scales are all inter-convertible but have different interval sizes and zero points. While Celsius and Kelvin share the same interval size, Fahrenheit's is smaller. The key conversion formulas that show their relationships are:

  • Celsius to Kelvin: K = °C + 273.15
  • Celsius to Fahrenheit: °F = (°C × 9/5) + 32
  • Kelvin to Celsius: °C = K - 273.15