Comparing Celsius and Fahrenheit temperature scales
About this video
The video compares the Celsius and Fahrenheit temperature scales. On Celsius, water freezes at 0 degrees and boils at 100; on Fahrenheit, it freezes at 32 and boils at 212. By matching where 0 °C lines up with 32 °F (and 100 °C with 212 °F), the narrator identifies which thermometer is which.
You'll be able to
- state the freezing and boiling points of water in Celsius and in Fahrenheit.
- use matching reference points to tell which thermometer is Celsius and which is Fahrenheit.
- explain why 0 °C and 32 °F are the same temperature.
Key words
- Celsius
- A temperature scale, used in most of the world, where water freezes at 0 degrees and boils at 100 degrees.
- Fahrenheit
- A temperature scale, used mainly in the United States, where water freezes at 32 degrees and boils at 212 degrees.
- freezing point
- The temperature at which liquid water turns to ice.
- boiling point
- The temperature at which water boils and turns into steam.
- standard temperature and pressure
- The normal conditions under which these freezing and boiling points are measured.
Transcript
Look at the two thermometers below. Identify which is Celsius and which is Fahrenheit, and then label the boiling and freezing points of water on each. Now, the Celsius scale is what's used in the most of the world. And the easy way to tell that you're dealing with the Celsius scale is on the Celsius scale, 0 degrees is freezing of water at standard temperature and pressure, and 100 degrees is the boiling point of water at standard temperature and pressure.
Now, on the Fahrenheit scale, which is used mainly in the United States, the freezing point of water is 32 degrees, and boiling of water is 212 degrees. As you could tell, Celsius, the whole scale came from using freezing as 0 of regular water at standard temperature and pressure and setting 100 to be boiling.
On some level, it makes a little bit more logical sense, but at least here in the U.S., we still use Fahrenheit. Now let's figure out which of these are Fahrenheit and which are Celsius. Now remember, regardless of which thermometer you're using, water will always actually boil at the exact same temperature.
So Fahrenheit, 32 degrees, this has to be the same thing as Celsius 0 degrees. So let's see what happens. So when this temperature right here is 0, this one over here, it looks like it's negative something. So this one right here doesn't look like Celsius. Here, if we say this is Celsius, this looks pretty close to 32 on this one.
Let me do that in a darker color. So this one right here looks like Celsius, and this one right here looks like Fahrenheit. And the way I was able to tell is that the 0 degrees Celsius needs to be the same thing as 32 degrees Fahrenheit. In both cases, this is where water freezes, the freezing point.
That is water freezing. And let's make sure we're right. So if this is the Celsius scale, this is where water will boil, 100 degrees Celsius, and that looks like it is right about 212 on the other scale. So right there is where water is boiling at standard temperature and pressure.
So this thing on the right, right here, I guess I'll circle it in orange, that is Celsius. And then the one on the left, I'll do it in magenta, the one on the left is Fahrenheit.
Video © Khan Academy, used under CC BY-NC-SA. Watch on Khan Academy. Puzzicle is not affiliated with Khan Academy.