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Temperature Conversion Explained: Celsius, Fahrenheit & More

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Step-by-Step Guide: Convert Between Celsius, Fahrenheit, and Kelvin

Conversion of temperature is the process of changing the value of temperature from one unit to another. There are many methods of conversion of temperature, among them Kelvin, Celsius and Fahrenheit are the most frequently used methods. According to the Kelvin scale, the freezing point of water is 273.15K and the boiling point is 373.15K and according to the Fahrenheit scale, the freezing point of water is 32°F and the boiling point is 212°F. In the same way, according to the Celsius temperature scale, the freezing point of water is 0°C and the boiling point is 100°C.


Celsius Scale 

The Celsius scale is also called the centigrade scale, and it is based on 0° C for the freezing point and 100° C for the boiling point of water. Initially, On the Celsius scale, 0° is used to denote the boiling point of water and 100° C to denote the freezing point of water. Further, these values were inverted 0° for the freezing point and 100° for the boiling point of water. This form of scale gained widespread use all over the world. 


Fahrenheit Scale 

This scale is based on 32° for the freezing point of the water and 212° for the boiling point of the water, the interval between the freezing point and the boiling point in being divided into 180 equal parts. The Fahrenheit temperature scale was first introduced in the 18th century by a German physicist named Daniel Gabriel Fahrenheit. Initially, he selected zero of his scale, as the temperature of the ice salt mixture.  And then selected the values of  30° and 90° for the freezing point of water and normal body temperature, Later they were revised to 32° and 96°. But, the final scale requires an adjustment to 98.6° for the latter value.


The Fahrenheit scale is used in the US and the Celsius or centigrade scale is used in most of the other countries, for scientific purposes worldwide. The conversion formula for a temperature that is expressed on the Celsius (°C) scale to its Fahrenheit (°F) formula is given below:

°F = (9/5 × °C) + 32.


Interactive Thermometer

[Image will be Uploaded Soon]

An interactive thermometer consists of the accompanying measures to illustrate the temperature as shown in the above figure. The scale is shown in both Celsius and Fahrenheit readings on either side. This ranges from 100°C to -40°C and is marked in intervals of ten degrees. A slider is dragged in the interactive thermometer to alter the measure. And note that the red ‘mercury’ level does not raise or lower on the interactive.


Conversion of Temperature 

Temperature Conversion Formulas 

There are mainly three types of temperature conversion given below:

  • Conversion Between Celsius and Kelvin

  • Conversion Between Fahrenheit and Kelvin

  • Conversion Between Celsius and Fahrenheit

The Formula Used for Temperature Conversion of Celsius and Kelvin is:

The formula used to convert temperature from Celsius to Kelvin is K = C + 273.15.

The formula used to convert temperature from Kelvin to Celcius is C = K − 273.15.

 

The Formula Used for Temperature Conversion of Fahrenheit and Celsius is:

The conversion of the temperature from Fahrenheit to Celsius formula is C = (F − 32) × 5 ⁄ 9.

conversion of the temperature from Celsius to Fahrenheit formula is F = C(9 ⁄ 5) + 32.

 

The Formula Used for Temperature Conversion of Fahrenheit and Kelvin is:

The formula used to convert temperature from Fahrenheit to Kelvin is, K = (F − 32) × 5 ⁄ 9 + 273.15.

The formula used to convert temperature from Kelvin to Fahrenheit is, F = (K – 273.15) × 9 ⁄ 5 + 32.

 

Fahrenheit to Celsius Chart Table 

Fahrenheit

Celcius 

Description

-459.67 °F

-273.15 °C

absolute zero temperature

50 °F

10.00 °C


32 °F

0 °C

freezing/melting point of water

70 °F

21.11 °C

room temperature

98.6 °F

37 °C

average body temperature

212 °F

100 °C

The boiling point of water

300 °F

148.89 °C



Temperature Conversion Formula Table

Unit

To Celsius

To Fahrenheit

To Kelvin

Celsius (C)

C (°)

C(9 ⁄ 5) + 32

C + 273.15

Fahrenheit

(F − 32) × 5 ⁄ 9

F

(F − 32) × 5 ⁄ 9 + 273.15

Kelvin

K – 273.15

(K – 273.15) * 9 / 5 + 32

K


Solved Example Question

Question 1: What is 30°C in Kelvin?

Solution:

The formula used to convert temperature from Celsius to Kelvin is, K = C + 273.15

K = 30 + 273.15 K = 303.15

 

Question 2: Convert 50°C to °F.

Solution:

Celsius to Fahrenheit conversion formula is given by:

°F = °C(9 / 5) + 32

= 50 (9 / 5) + 32

= 90 + 32

= 122

Therefore, 50°C = 122°F

 

Question 3: Convert 113°F to Kelvin.

Solution:

Fahrenheit to Kelvin conversion formula is given by:

K = (F − 32) × 5 / 9 + 273.15

= (113 – 32) × (5 / 9) + 273.15

= 81 × (5 / 9) + 273.15

= 45 + 273.15

= 318.15

Therefore, 113°F = 318.15 K

 

Question 4: Convert 225 K to Celsius.

Solution:

Kelvin to Celsius conversion formula is given by:

C = K – 273.15

= 225 – 273.15

= -48.15

Therefore, 225 K = -48.15°C

FAQs on Temperature Conversion Explained: Celsius, Fahrenheit & More

1. What are the fundamental formulas for temperature conversion between Celsius, Fahrenheit, and Kelvin?

The three primary formulas for converting between the most common temperature scales are:

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

These formulas are essential for solving a wide range of scientific and mathematical problems.

2. How can you convert a specific temperature, for example, 25°C, to Fahrenheit?

To convert 25°C to Fahrenheit, you use the formula °F = (°C × 9/5) + 32. Here is the step-by-step calculation:

  • First, multiply the Celsius temperature by 9/5: 25 × 9/5 = 45.
  • Next, add 32 to the result: 45 + 32 = 77.

Therefore, 25°C is equal to 77°F.

3. What is the main difference in the scales of Celsius and Kelvin?

The primary difference between the Celsius and Kelvin scales is their zero point. The size of one degree is the same in both scales. However, 0°C is the freezing point of water, whereas 0 K is absolute zero, the lowest possible theoretical temperature. Because of this, the Kelvin scale is an absolute scale and is standard in many scientific fields.

4. Why is the Kelvin scale preferred over Celsius and Fahrenheit in scientific calculations?

The Kelvin scale is preferred in science because it is an absolute temperature scale. Its zero point, 0 K (absolute zero), represents the complete absence of thermal energy. This makes it directly proportional to the kinetic energy of particles. This property is crucial for many scientific laws, such as the Ideal Gas Law, where using Celsius or Fahrenheit would require complex adjustments.

5. Why do different countries use different temperature scales like Celsius and Fahrenheit?

The use of different scales is largely historical. The Fahrenheit scale was developed first and became standard in the British Empire, which is why countries like the United States still use it for daily weather and domestic purposes. Most of the world later adopted the metric system, which includes the Celsius scale due to its simpler reference points: 0°C for water's freezing point and 100°C for its boiling point.

6. Is it possible for a temperature to be a negative value on all three scales?

No, it is not. Negative values are common on both the Celsius (e.g., -15°C) and Fahrenheit (e.g., -5°F) scales. However, the Kelvin scale cannot have negative values. This is because its starting point, 0 K, represents absolute zero, the lowest temperature that can exist. Therefore, there is no temperature below 0 K.

7. How does temperature conversion apply in real-world situations?

Temperature conversion is used frequently in daily life. For example:

  • Cooking and Baking: Recipes from other countries often require converting temperatures from Celsius to Fahrenheit, or vice-versa, to set an oven correctly.
  • Weather Forecasting: International weather reports may use Celsius, which people in countries using Fahrenheit need to convert to understand the forecast.
  • Health: Clinical thermometers measure body temperature, and understanding the conversion is important for international health standards.