Science Chapter 7 Heat Pmr

HEAT

DIFFERENCES

TEMPERATURE

Form of energy

Definition

Is the degree of hotness or coldness an object.

Joule(J)

Symbol & unit

Hot to cold area

Process to happen

Degree Celsius ( ̊ C) or SI unit kelvin (K) Movement of particles increases when the number of particle increases

CONDUCTION

CONVECTION

RADIATION

solid

liquid, gas

Vibrated particles collide with other particles Fast process

Hot to cold area

Solid, liquid, gas, vacuum Without any medium

Slow process

Very fast process Sea breeze - During day

Chapter 7: Heat- form of energy EXAMPLES OF SOURCES OF HEAT Sun/solar (main source)=drying wet clothes Chemical=preserving food (kill bacteria) Nuclear=melting iron from ores Electrical=generate electric (produce steam) Friction= rub two stone to produce heat Mechanical=car is moving

- land hot faster - sea hot slow

Land breeze - during night - land cold faster - sea ‘baru nak’ hot

When heated things expand When cooled things contract

Air move from cold to hot

Bimetallic strips- metal which easily expand S>R>Q>P

Heat conductor - metals Heat insulator - non-metals Heat absorber/radiator - dark, black, dull Heat reflector - shiny, white Sequence drop of Thumbtacks

A, B

Sublimation

Melting

SOLID

Boiling/ evaporation

LIQUID

Freezing

GAS

Condensation

Sublimation

NAFI ‘O9