The celcius was designed without regard to the temperature of absolute zero. Why does the exact value of absolute zero only have 2 decimal points in the celcius scale?

Question

Isn’t it quite a big coincidence that this value would only have 2 decimal points on a scale that puts the temperature value of water boiling and freezing at whole numbers?

In: Mathematics

Answer 1

They changed the Celsius scale to make that work. -273.16°C is absolute zero, by definition. And 0.01°C is the temperature of water at its triple point, by definition.*

Defining the Celsius scale this way is more precise than the classic freezing/boiling point of water definition, since the temperatures at which water freezes and boils can vary depending on several things, in ways that absolute zero and the triple point don’t.

^(*This definition is no longer in use as of 2019. Now, the degree Celsius is defined in terms of absolute zero and the Boltzmann constant, which relates temperature and energy across the universe. But the value we assign that constant was chosen to keep the degree Celsius as close as possible to the prior water-based definition.)