Celsius Scale (Centigrade)
Definition and meaning of Celsius Scale (Centigrade) in chemistry.
The Celsius scale is a standard temperature system used in science and daily life. It sets the freezing point of pure water at exactly 0 degrees. It sets the boiling point of water at 100 degrees under normal atmospheric pressure.
In more detail
Swedish astronomer Anders Celsius invented this measuring system in the year 1742. He originally put the freezing point at 100 and the boiling point at 0. Other scientists soon flipped the numbers into the logical modern form we use today.
For many years, people called it the centigrade scale instead of the Celsius scale. The prefix centi means hundred, and the word grade means steps. This name perfectly described the one hundred exact divisions between freezing and boiling.
In 1948, a global committee officially changed the name to honor Anders Celsius. They also wanted to avoid confusion with a geometry angle unit called a centigrade. Today, the Celsius scale links directly to the Kelvin scale used by all chemists.
A change of one degree Celsius is exactly the same size as one kelvin. This shared size makes converting between the two temperature scales very simple. You just add or subtract the number 273.15 to move between them.
A common student misconception is that 0 °C means there is no heat energy left. True zero energy only happens at absolute zero, which sits at -273.15 °C.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | °C |
| Freezing point of water | 0 °C |
| Boiling point of water | 100 °C |
| Conversion to Kelvin | K = °C + 273.15 |
| Named After | Anders Celsius |
You might set a laboratory water bath to hold a steady 37 °C for a biology experiment. This value matches the average normal body temperature for a healthy human being. If you need to record this in official scientific units, it equals 310.15 K. If you need to share it with an American audience, it equals 98.6 °F.
Frequently asked questions
Is centigrade the exact same thing as Celsius?
Yes. They describe the exact same temperature scale. The official scientific name changed to Celsius in 1948 to avoid confusion with an angle measurement.
How do you convert a temperature from Celsius to Fahrenheit?
You multiply the Celsius temperature by 9/5 and then add 32. For example, a boiling temperature of 100 °C equals 212 °F.
Why are Celsius and Kelvin degrees the same size?
Scientists designed the Kelvin scale specifically to match the step size of Celsius. This makes scientific calculations much simpler to manage.