PCS701_science_6

43 terms · PCS701_science_6

Temperature

is the degree of hotness or coldness of the body

Heat energy is the form of energy

that flows from a hot body to a cold body

conduction

conduction is a form of heat transfer that happens

when two solid bodies are in contact with each other

coductor is a substance

that conduct heat easily

insulator is a substance that

does not conduct the heat easily

convection is the method by which the heat

is transferred by the mass movement of the liquid or the gas

radiation is a mode of heat transfer that

does not need a medium

thermometer is a

device used to measure the temperature

two most common liquids used in the thermometer are

mercury and alcohol

modern digital thermometers are

quite accurate and easy to read

heat will flow from a hot body to a cold body until

both of them reach the same temperature

heat energy is measured in

calories and joules

is conduction

is convection

the bodies that are black

absorbs more heat than bodies that are white

most commonly used reference temperatures are

melting point of ice and boiling point of water

two commonly used temperature scales are

Celsius and Fahrenheit

On the Celsius scale the melting

point of ice is 0 degree centigrade and boiling point of water is 100 degree centigrade. the difference between these two points are divided into 100 degrees

On the Fahrenheit scale, the melting point

of ice is 32 degrees Fahrenheit and the boiling point of water is 212 degree Fahrenheit. Difference between two points are divided in to 180 degrees

melting point and boiling point of mercury are

//1// mercury remains liquid for wide range of temperatures -38.87 to 357.58 //2// silver colour, so easy to read //3// does not stick to the glass //4// uniform rate of expansion over a wide range of temperatures

//1// cheaper and less harmful than mercury //2// measure much lower temperatures like -115 degree centigrade

Disadvantage of the mercury thermometer are

//1// more harmful than alcohol thermometer //2// cannot measure temperatures below -38.87

//1// difficult to read compared to mercury //2// cannot measure temperatures above 78 degree centigrade

thermometer used to measure the body temperature is called

clinical thermometer

clinical thermometer is generally

a mercury thermometer, but now a days digital thermometers are becoming popular

Two characteristic features of the clinical thermometers are

//1// a little arrow showing normal body temperature 98.4 and 98.6 //2// there is a kink in the tube near the buld which prevents the mercury from contracting before the temperature is even read

precautions to be used in clinical thermometer are

//1// was before and after use using antiseptic //2// do not break the bulb, mercury is dangerous to health, a toxic substance

heat energy is measured in

joules in SI units, the symbol is J

matter is made up of tiny particles called

atoms and molecules

heat energy increases

the vibrations of particles in the solid when heated

woolen cloths keeps us worm

because they have tiny curls called crimps and they create a small air pocket. there air pockets insulate and prevent the heat loss, thus keeps us worm

SEA breeze comes

during the later afternoon

during the night

warn air

raises upwards

travel like light rays, both in vaccum and in air medium.

in a thermal flask, conduction loss is reduced by

having a insulating material outside

in a thermal flask, convection loss is reduced by

keeping vacuum between outer and inner walls

in a thermal flash, radiation loss is reduced by

keeping a highly reflective material to send the heat back to the jar