Effects of Heat and its transmission
Definitions
Heat
a form of energy
when heat is supplied to a substance, its temperature increases
Temperature
measure of the degree of hotness or coldness of an object
S.I unit of temperature is K (kelvin), common unit is degree culsius
Concepts
Thermal energy flows from a region of high to low temperature
Conduction
Radiation
Convection
process of thermal energy transfer through a medium from the movement of one particle to another
Process
when heated, particles at the heated end vibrate more and more, transfer heat to neighbouring particles
Gain heat
Gain (more) kinetic energy
particles move faster (based on their respective motion)
The distance between each other increase (depends on how far apart they move)
Volume of matter increase, density decrease
Matter expands
process of thermal energy transfer through a medium without the movement of the particles in the medium
The greater the temperature difference, the faster heat flows
Conduction
- Heat travels from a ... to a ...
Convection
Can only take place in gas and liquids
Take place in all states
Hot air/fluid rise, cool air/fluid sinks
Convection current is set up
heat transfer by the emission of infrared waves
Radiation
Requires no medium, can take place in a medium
Radiator/emitter
Absorber
Reflector
Factors of radiation
Surface area
Colour/ texture
Temperature
Dull, black, rough surface
Radiates and absorbs faster
Smooth, white, shiny surface
radiate and absorb slower
larger surface
radiate/absorb faster
Smaller surface
radiate/absorb slower
Hotter
Cooler
Radiate (absorb?) faster
radiate (absorb?) slower
increase in temp is also affected by volume
Density = Mass/Volume
does not affect size of atoms, only distance between each atom
- heat is conducted away from - conducted to/ .... by conduction
density decrease/increase
gain heat converted to kinetic energy, move further apart and expand
Radiant heat
all objects can absorb or emit radiant heat
good reflectors of heat
poor reflectors of heat
always look out for what factor the object is supposed to function for, and predict
also, look out for these properties in objects!