chap 9 Flashcards
Heat is a form of
energy
heat flows from a:
hotter region to a colder region
what does temperature mean
- a measure of the degree of hotness or coldness of an object
State a few characteristics of heat that makes it different from temperature
heat:
- form of energy
-measured in joule (J)
- amount of heat depends on the type of material, quantity of material & temp
State a few characteristics of temperature that makes it different from heat
temperature:
-the degree of hotness or coldness of an object
- measured in degree celsius (C) or kelvin (K)
- depends on the degree of movement of the particles in a matter
Heat flow happens in 3 ways:
- conduction
-convection
-radiation
Elaborate on conduction
- process of heat transfer frm hotter regions to colder regions through a solid medium
- particles that receive heat energy will vibrate and collide more frequently and transfer the heat to the whole medium
elaborate abt convection
- heat is transferred by the movement fluid (liquid gas) from hotter regions to colder regions
- part of the fluid that receives heat will expand, become less dense and rise
- colder n more dense fluid moves downwards
- circulating stream that rises and falls continuously is known as convection current
elaborate about radiation
- process of transferring heat without any medium
- heat can propagate through an empty space or vacuum
- the types of surface, temp and total surface area of an object will influence the rate of heat flow
heat energy frm the sun is transferred to the earth through
radiation
The warming of the earth by the sun causes changes in climate and the occurrence of natural phenomena such as:
sea breeze, land breeze, thunderstorms
Elaborate abt sea breeze
- formation of land breeze and sea breeze r examples of a natural convection process
- Sun heats up the land faster than sea during the day
- warm air on land expands, becomes less dense and rises bcuz its lighter
- cold air from surface of the sea that is more dense is drawn in to replace the warm air on land n results in sea breeze
elaborate on land breeze
- land cools faster than the sea at night
- air above sea which is warmer becomes less dense n rises
- the cold n more dense air from land begins to move the sea resulting in land breeze
Head conductors are
Materials that allow heat flow
Heat insulators are
materials that prevent heat flow
two objects which are in thermal contact can :
exchange heat energy between them
when there is no net transfer of heat energy between the objects, the objects are said to be in:
thermal equilibrium
two objects that are in thermal equilibrium have:
the same temperature
Explain how heat effects solids
- particles in a solid vibrate at a fixed position
- the particles vibrate faster n move further apart when heated
- this causes the volume of the solid to increase bcuz the solid expands
- particles vibrate slower n move closer when cooled
- causes the volume to decrease bcuz solid contracts
explain how heat effects liquid and gas
- particles in liquid and gas move freely
- the particles move faster n randomly n the distance between them increases when heated
- causes the volume of liquid n the gas to increase bcuz the liquid n gas expand
Name some uses of expansion n contraction of matter in daily life
- thermometer
- steel bridges
- railway tracks
- bimetallic strip
The ability of an object to absorb or radiate heat depends on the:
type and colour of its surface
when an object radiates heat, its:
temperature decreases
