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Fahrenheit, Celsius and Kelvin
The first accurate thermometer was invented by Gabriel
Daniel Fahrenheit, a German physicist, in the early 1700s.
Fahrenheit created a scale for his thermometer and named each
unit of change a degree. The temperature measured on the
Fahrenheit scale is written as ‘F’, which means ‘degrees
Fahrenheit.’ On this scale, at standard sea level atmospheric
pressure, water freezes at 32 F and boils at 212 F.
In 1742, Anders Celsius, a Swedish astronomer, created a
new scale for measuring temperature. The Celsius scale put the
freezing point of water at 0 C (zero degrees Celsius) and the
boiling point of water at 100 C. The Celsius scale - also known as
the centigrade scale - is the world standard for measuring
temperature.
Scientists use another temperature scale called the Kelvin
scale. It was devised around 1850 by the British scientist William
T.Kelvin. On the Kelvin scale, one degree of change is the same as
one degree of change on the Celsius scale. But the freezing point
of water is measured at 273 K (degrees Kelvin) and the boiling
point at 373 K. Zero degree on the Kelvin scale means absolute
zero, or the point at which an object has no heat.

Comprehension Questions

I. Say which of the following statements are false and
which are true. Correct the false statements to make them
true.
1. Fahrenheit invented the first accurate thermometer.
2. Anders Celsius created a new scale for measuring
temperature.
3. Centigrade scale is not the world standard for measuring
temperature.
4. The Kelvin scale was devised by the British scientists
William T.Kelvin.
5. On the Kelvin scale the freezing point of water is measured
at 0 C (zero degree Celsius)

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