Watch the news. -.-
thermoneter
Temperature is the measure of thermal energy. And how you measure thermometers is that if the liquid expands when its temperature increases. The height of a column of the liquid inside the tube shows the temperature.
Celsius
A thermometer can be used to measure the temperature outside. Digital thermometers, mercury thermometers, and infrared thermometers are commonly used for this purpose.
They had thermometers that were a glass tube with mercury sealed inside. There were temperature markings on the outside of the tube that when the mercury reached that point it showed what the temperature was.
Well it won't work below freezing.
Boiling is way far outside its operating range.
Temperature xD
You measure temperature using a thermometer.
With a tape measure. You asked. Outside to outside, top to bottom.
outside to outside