Measure of hotness or coldness of a body.

Basins of hot cold water the realitivity of feeling.

Take 3 basins fill one with hot water (not too hot to harm anyone) one with cold water (put in some ice a while before hand), and one with some tap water that has been left out for a while.

Put one hand in the hot water and at the same time put another hand in the cold water. Leave them in there for about 20 seconds.

Replace both hands in the medium temperature water.

Express and explain your feelings,


Feelings of heat are relative to temperature of body previously.

Temperature is a measure of hotness (or coldness) of a body

The SI unit of temperature is the kelvin

The definition of unit in terms of the triple point of water not required.

Temperature is the average kinetic energy of the particles (atoms) within the body.

Tk = 0K is absolute zero.

Therefore at this temperature the average kinetic of the particles is zero.

What is kinetic temperature again?

Ek so how does that ever get to zero?

Does the mass dissappear? Can it ?

ah the velocity of the particles goes to zero (brushing quickly over quantum effects)

Did you hear about the man that got cooled to Absolute Zero?

He's 0k now

Celsius scale is the practical temperature scale t /ºC = T /K – 273.15

Lord Kelvin (William Thomson), wrote in his paper, On an Absolute Thermometric Scale, of the need for a scale whereby "infinite cold" (absolute zero) was the scale’s null point, and which used the degree Celsius for its unit increment. Thomson calculated that absolute zero was equivalent to −273 °C on the air thermometers of the time.[1] This absolute scale is known today as the Kelvin thermodynamic temperature scale. Thomson’s value of "−273" was the reciprocal of 0.00366 - the accepted expansion coefficient of gas per degree Celsius relative to the ice point, giving a remarkable consistency to the currently accepted value.


Resolution 3 of the 10th CGPM gave the Kelvin scale its modern definition by designating the triple point of water as its second defining point and assigned its temperature to exactly 273.16 kelvin.

but instead prefer the Celcius scale, that was devised by the Swedish astronomer, Anders Celcius in 1742.

However Anders made the freezing point of water 100 oC and the boiling point of water at 0 oC.

It took the father of taxidermy Carl Linnaeus (a fellow Swedish scientist) to reverse the scale, he took this decision to make the measurements easier to make sense of.

t /ºC = T /K – 273.15

If you are interested the farenheit scale definition points are

Farenheit 0 @ freezing of salt & water

Farenheit 100 @ body temp

Some popular / interesting temperatures on this page


really good, read the whole lot

The definition of unit in terms of the triple point of water not required.

Triple point of water

The single combination of pressure and temperature at which liquid water, solid ice, and water vapour can coexist in a stable equilibrium occurs at exactly 273.16 K (0.01 °C) and a partial vapour pressure of 611.73 pascals