TEMPERATURE - matter is made up of atoms and molecules. these atoms and molecules are in regular movement in solids and random movement in liquids an gases. hence they posses kinetic energy. which is responsible for hotness and coldness of the body. temperature is the measure of the hotness and coldness of the body when the body is heated its molecules are in vigorous movement therefore have a high energy and the body is said to be in high temperature.when abodyis cooled lower and lower,its kinetic energy decrease and body is said to be in lower temperature. temperature is measure in degrees with help of thermometers.there two scales of temperature namely centigrade scale and absolute scale.
Centigrade Scale In the centigrade scale of temperature, the temperature of the melting point of ice is taken as 0°C and temperature of the boiling point of water is taken as 100°C. The interval between the two is divided into 100 degrees. The scale is also called as Celsius scale.
Absolute scale In the absolute scale of temperature 0 degree
is named as absolute zero and it is denoted as OK. The absolute zero is the
temperature at which the molecules will have zero speed. The O K temperature is
equal to -273°C in centigrade scale. The temperature of melting ice is taken as
273 K and the temperature of boiling water is taken as 373 K. The interval
between the two is divided into 100 degrees. One degree interval is the same in
both centigrade and absolute scale of temperature. The absolute scale is also
known as Kelvin scale of temperature. In the SI system of units, the absolute
scale is used. .
HEAT - heat is form of energy which can be transferred from one place to another. if a hot body and cold body are place in close contact , the hot body will transfer some of its heat until the temperature of two remain equal. there are three method of heat transfer. they are conduction, convection and radiation. conduction is the process in which heat energy is transferred without the visible motion of the particles of the heated body, conduction is take place in solid , liquid and gases. metals in general are good conductors of heat ,e.g silver,copper,etc. nonmetals are bed conductor of heat e.g glass rubber,wood,etc.convection is the process in which heat energy is transfers by the actual motion of the particles of the body. convection takes place in liquid and gases e.g trade winds, land and sea breezes. radiation is the process by which heat energy is transfers from one place to another without the aid of any material medium e.g heat reaches from the sun the si unit of the heat is joule
0 comments: