Measuring Temperature

In this video, I compare different measurements in Kelvin,Celsius, and Fahrenheit,
Kelvin is the SI unit of measurement and absolute zero is 0 on the Kelvin scale.
Celsius is a derived unit. For each type of temperature measurement I got through the temperature at freezing,boiling, and absolute zero.

At 0:44 I mispronounce -273.15 by saying point instead of "and"
sorry for the mistake.

[MooMooMath]

Thanks for checking out my video. At 0:44 I mispronounce -273.15 by saying point instead of "and"
sorry for the mistake.

[TraceguyRune]

In 1908, Scientists achieved −269°C/1.5k on Earth. What did they use to measure and confirm that?