What Is Fahrenheit (°F)?
Fahrenheit is a scale that measures how hot or cold something is. It is written with the symbol °F and is often used for weather, room temperature, and cooking in some countries.
Definition
The Fahrenheit scale is a way to measure temperature using degrees Fahrenheit.
- Water freezes at 32 °F.
- Water boils at 212 °F at normal air pressure at sea level.
- The scale is divided into equal steps called degrees.
The distance between freezing and boiling of water on this scale is 180 degrees. So each degree Fahrenheit is one 180th of that temperature gap.
History / Origin
The Fahrenheit scale was created in the early 1700s by a German Polish scientist named Daniel Gabriel Fahrenheit.
- He first made very accurate thermometers using mercury.
- He then created a temperature scale so people could read his thermometers easily.
- He chose three points to build his scale, including a cold salt and ice mixture and the freezing and body temperature of people.
Over time, his original exact points were adjusted. Today people define Fahrenheit using the freezing and boiling points of water and also by linking it to the Kelvin scale, which scientists use as the main temperature scale.
Symbol & Abbreviation
The unit is written as degrees Fahrenheit.
- Symbol °F
- Full name degree Fahrenheit for one degree, degrees Fahrenheit for more than one
- Example 68 °F is a common room temperature.
The small circle ° means degree, and the F stands for Fahrenheit.
Current Use Around the World
Today most countries use the Celsius scale, not Fahrenheit, for everyday life and for science. But Fahrenheit is still common in some places and for some uses.
- Countries that mainly use Fahrenheit United States, some Caribbean nations, and a few others use °F for weather reports and daily temperatures.
- Weather Many American weather apps, TV reports, and websites show temperatures in °F.
- Home and daily life Thermostats, air conditioners, and some medical thermometers in the US often show °F.
- Cooking Many recipes and ovens in the US use °F settings.
In science, engineering, and most international work, Celsius and Kelvin are preferred, but you may still see Fahrenheit used in some older books, tools, and industries in the United States.
Example Conversions
It is useful to change temperatures between Fahrenheit and Celsius. Here are simple rules and examples.
From Fahrenheit to Celsius
Use this method.
- Step 1 subtract 32 from the Fahrenheit value.
- Step 2 multiply the result by 5.
- Step 3 divide that result by 9.
Formula in short form.
°C = (°F - 32) × 5 ÷ 9
Examples
- 32 °F to Celsius
32 – 32 = 0, 0 × 5 ÷ 9 = 0 °C. So freezing point of water is 32 °F and 0 °C. - 68 °F to Celsius
68 – 32 = 36, 36 × 5 = 180, 180 ÷ 9 = 20 °C. - 98.6 °F to Celsius normal body temperature
98.6 – 32 = 66.6, 66.6 × 5 = 333, 333 ÷ 9 ≈ 37 °C.
From Celsius to Fahrenheit
Use this method.
- Step 1 multiply the Celsius value by 9.
- Step 2 divide that result by 5.
- Step 3 add 32.
Formula in short form.
°F = (°C × 9 ÷ 5) + 32
Examples
- 0 °C to Fahrenheit
0 × 9 = 0, 0 ÷ 5 = 0, 0 + 32 = 32 °F. - 20 °C to Fahrenheit
20 × 9 = 180, 180 ÷ 5 = 36, 36 + 32 = 68 °F. - 100 °C to Fahrenheit boiling point of water
100 × 9 = 900, 900 ÷ 5 = 180, 180 + 32 = 212 °F.
Related Units
Fahrenheit is one of several temperature units. Others include.
- Celsius (°C) The most common everyday temperature scale in the world. Water freezes at 0 °C and boils at 100 °C.
- Kelvin (K) The main unit for temperature in science. The Kelvin scale starts at absolute zero, the coldest possible temperature, where particles have almost no movement.
- Rankine (°R or °Ra) A temperature scale used in some engineering fields in the past. It is like Kelvin but starts from absolute zero and uses Fahrenheit sized degrees.
Fahrenheit, Celsius, and Kelvin are all linked by fixed formulas, so you can always convert from one to another.
FAQs
What is special about the Fahrenheit scale
On the Fahrenheit scale, the freezing and boiling points of water are 180 degrees apart, from 32 °F to 212 °F. This makes each degree a smaller step than a Celsius degree, so some people feel it gives more detail for everyday temperatures.
Why do some countries still use Fahrenheit
The main reason is history and habit. The United States and a few other places have used Fahrenheit for a long time. Many people there are used to thinking in °F for weather and cooking, so they keep using it.
Is Fahrenheit part of the metric system
No. The metric system uses Celsius for everyday temperature and Kelvin for science. Fahrenheit belongs to the older imperial and US customary systems.
How can I quickly estimate Fahrenheit from Celsius in my head
A quick trick is. double the Celsius temperature and then add 30. This is not exact but often close. For example, 20 °C, double is 40, plus 30 is about 70 °F. The exact answer is 68 °F.
Which scale should I use, Fahrenheit or Celsius
Use the scale that is common in your country or required by your school or job. If you work in science or with people from many countries, it is best to know Celsius and Kelvin and also be able to convert from Fahrenheit.
