Rankine scale facts for kids
The Rankine scale is a way to measure temperature. It's an "absolute" scale, which means it starts at the lowest possible temperature, called absolute zero.
The Rankine scale is a bit like the Kelvin scale because both start at absolute zero. So, 0 degrees Rankine (written as 0 °Ra) is the same as 0 Kelvin (0 K).
However, the Rankine scale is different because its steps are the same size as those on the Fahrenheit scale. This means if the temperature goes up by 1 °Ra, it's the same as going up by 1 °F. This is different from the Kelvin scale, where a 1 K change is like a 1 °C (Celsius) change.
Contents
What is the Rankine Scale?
The Rankine scale helps scientists and engineers measure very cold temperatures. It was created by a Scottish engineer named William John Macquorn Rankine in 1859. This scale was mostly used in the United States.
How Does Absolute Zero Work?
Absolute zero is the coldest possible temperature in the universe. At this temperature, particles (like atoms and molecules) stop moving completely.
- On the Rankine scale, absolute zero is 0 °Ra.
- On the Kelvin scale, absolute zero is 0 K.
- On the Celsius scale, absolute zero is about -273.15 °C.
- On the Fahrenheit scale, absolute zero is about -459.67 °F.
Comparing Rankine with Other Scales
Let's look at how the Rankine scale compares to other common temperature scales:
- Rankine and Fahrenheit: These two scales are closely related. A change of one degree on the Rankine scale is exactly the same as a change of one degree on the Fahrenheit scale. The main difference is where they start: Fahrenheit has a freezing point of water at 32 °F, while Rankine starts at absolute zero (0 °Ra).
- Rankine and Kelvin: Both of these are "absolute" scales, meaning they start at absolute zero. The difference is the size of their degree steps. Kelvin uses the same step size as Celsius, while Rankine uses the same step size as Fahrenheit.
- Rankine and Celsius: These scales have different starting points and different step sizes. Celsius uses 0 °C for the freezing point of water, and its degrees are larger than Rankine degrees.
Why Was the Rankine Scale Used?
The Rankine scale was useful in engineering, especially in countries that used the Fahrenheit scale. It allowed engineers to work with absolute temperatures (starting from absolute zero) while still using the familiar Fahrenheit degree size. This made calculations simpler for some engineering problems.
