Thermal energy Flashcards
What is conduction?
The process by which thermal energy is transmitted through a medium from one particle to another.
Why are liquids and gases poorer conductors of thermal energy?
Collisions between molecules in liquids and gases are less frequent than that in solids.This si because the molecules are further apart.
A blanket keeps people warm.Why?
A blanket is made up of wool.Wool is a poor conductor of thermal energy.Air is trapped in the wool.Air is a very poor conductor of thermal energy.Thermal energy does not quickly conduct through it.Therefore, the blanket reduces the loss of thermal energy from the body by conduction.
What is convection?
Convection is the process by which thermal energy is transmitted from one place to another by the movement of heated gas or liquid.
What is radiation?
The process by which thermal energy is transferred by infra-red rays.
Rate of energy transfer by radiation is affected by…
Colour and texture of surface
Surface temperature
Surface area
Why are teapots usually made of shiny metal?
A shiny surface is a poor emitter of infra-red rays.Less thermal energy will be lost to the surroundings by radiation and the contents in the teapot will stay warm longer.
Purpose of cooling fins
To increase the surface area for a bigger ray of emission
