Heat and Temperature

Temperature• The degree of hotness or coldness of a

body or environment.• One of the methods of measuring hotness

or coldness is the sense of touch.

Measurement of temperature• Temperature is measured with the help of

an Instrument called thermometer.

Temperature scales• CELSIUS• FAHRENHEIT• KELVIN

• Now we will only learn about Celsius and Fahrenheit scales.

C F

Celsius scales

• Indicated as C .• Most commonly used.• Named after Anders Celsius.• On this scale, Melting of Ice is taken as 0 C and boiling of water is taken as 100 C.

Fahrenheit scales

• Indicated as F.• Named after Gabriel Fahrenheit.• On this scale,32 F is taken as melting

point of ice and 212 F is taken as the boiling point of water.

Conversion formulae

Fahrenheit to Celsius Formula:- F=(C X 9/5) + 32 Example- Q. 45 C to F F= (45 X 9/5) +32 F= 81+32 F=113

Celsius to Fahrenheit Formula:- C= 5/9 (F-32)ExampleQ. 86 F to C C= 5/9 (90-32) C= 5/9 X 58 C= 32.2

Types of thermometers

• Mercury thermometer• Alcohol thermometer• Electrical thermometer

Mercury Thermometer

• Gabriel Fahrenheit invented the first mercury thermometer.

• Mercury melts at -38.87 C and boils only at 356.58 C.

• It is easier to see because of its silver colour.

Alcohol thermometer

• Alcohol thermometers are rarely used.• They are less harmful than mercury.• It melts at -155 C and boils at 78 C.

Electronic thermometers

• Nowadays electronic thermometers are used mostly.

• They can measure only body temperature from 36 C to 41 C.

Thank You !!!