Temperature is the degree of hotness or coldness of a body. The S.I unit of temperature is a kelvin (K).

(a) Thermometery.

A thermometer is an instrument which is used for measuring temperature on the basis of certain physical properties which change with changes in temperature.
These properties are called thermometric properties

Thermometric properties
A thermometric property is a property of a substance which continuously change with temperature and may be used for temperature measurements, these include:
-Increase in length.
-Change in potential difference
-Change in volume
-Change in pressure.

Thermometer scales.
There are 3 thermometer scales commonly used
(i) Celsius / centigrade scale (0C)
(ii) Fahrenheit scale (0F)
(iii) Kelvin scale/ absolute (k)

Relation between Celsius and Fahrenheit

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And if Celsius scale reads 1000c then

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Converting from Fahrenheit to Celsius.

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Relationship between Celsius scale and Kelvin scale

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Where C is temperature in Celsius scale and K is temperature in Kelvin scale.


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To obtain a standard scale on a thermometer. Two fixed points must be marked out on it. The upper and lower fixed points.