HEAT:
        Heat is a form of energy. It flow from hot body to cold body.
The flow of heat stops when the temperature of two bodies is ame. The bodies are said to be in "THERMAL EQUILIBRIUM" .
        The heat lost by hot body is equal to the heat gained by the cold body. This is known as "LAW OF HEAT EXCHANGE".

          Mathematically,

                              ΔQ  = ΔQ  

                                                     Lost     Gained  

UNITS:-
          The heat is measured in joules (J), Calorie is old unit of heat.
                                  4.2 cal  =  1j.
TEMPERATURE:-
                             The temperature determines the direction of the flow of heat. When , two bodies are brought in to thermal contact.

THERMOMETER

It is an instrument which is used to measure the temperature . It consists of a capillary glass tube, having bulb at the one end. The bulb is filled with mercury, the melting of ice and boiling point of water are marked on it.

Scales of temperature 

The following on the scales of the temperature

1) Celsius - OR Centigrade scale:-

                                                         In this scale the melting point of ice is snaked at '0' and boiling point of water is marked at '100'. The interval b/w these two fixed points it in divided into hundred (100) equal parts each part is called centigrade degree (1°C)

Fahrenheit Scale:-

                              In this scale melting point of ice is marked 32 boiling point of water 212. The internal is divided into 180 equal parts.

        The centigrade scale and Fahrenheit scale are related as

                        C   =  F - 32 

                        100        180

      OR             C  =  F - 32

                         5          9

3) Kelvin Scale -OR- Absolute scale:-

                                                            In this scale the melting point of ice is marked 273 and boiling point mete   r marked 373, the internal is divided into 0 equal parts, this means that the magnitude of Celsius degree and kelvin degree is same

                   They are related as

                                                   K°= °C+273.

Relation b/w Kelvin and Fahrenheit scale is

                                                   F° =  5°C (F-32) =273.

  All the following three scales of temperature are gives as the following figure.

                          °C            F°            K°    

                          100        212           273

                    ⇧        ⇧          ⇧ 

                   100     180       100

                      

                                       

                         ↓         ↓              ↓

                        0         32          273.