P1.1 - The transfer of energy by heating Flashcards
In terms of infrared radiation, all objects…
…emit and absorb it
What effect does a higher temperature have on the amount of infrared radiated?
It causes more IR radiation to be emitted.
What kind of surfaces are good emitters/absorbers of IR radiation?
Dark, matt surfaces
What kind of surfaces are poor emitters/absorbers of IR radiation?
Light, shiny surfaces
What kind of surfaces are good reflectors of IR radiation?
Light, shiny surfaces
How are the particles in solids, liquids and gases different?
They have different amounts of energy
What does kinetic theory explain?
The properties of different states of matter
What 4 methods of energy transfer involve particles?
Conduction, convection, condensation and evaporation
What is conduction?
Heat moving through a substance
What is convection?
When particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat
energy.
What is condensation?
A gas changing into a liquid
What is evaporation?
A liquid changing into a gas
How can the rate of condensation be affected?
-if the temperature of the gas is decreased, the rate of condensation is increased
How can the rate of evaporation be affected?
- if the temperature of the liquid is increased, the rate of evaporation is also increased
- air is moving over the surface of the liquid
- the surface area of the liquid is increased
What factors does the rate at which an object transfers energy depend on?
- surface area and volume
- the material from which the object is made
- the nature of the surface with which the object is in contact
The bigger the temperature difference between and object and its surroundings…
…the faster the rate at which energy is transferred by heating
What do U-Values measure?
How effective a material is at insulating
The lower the U-Value…
…the BETTER the material is at insulating
Why may solar panels contain water?
The water can be heated b the sun, then used to heat buildings or provide domestic hot water
What is the specific heat capacity of a substance?
The amount of energy required to change the temperature of one kilogram of the substance by 1 degrees Celcius
How can the energy transferred be worked out?
Energy = mass x specific heat capacity x temperature change
