P1.1 Energy Transfer By Heating Flashcards
______ objects give off more infrared radiation.
Hotter
What is infrared radiation emitted by?
All objects
How does temperature effect how infrared radiation is emitted?
The hotter the object the more infrared radiation it emits.
Why is a vacuum?
???
How is infrared radiation transferred?
By all electromagnetic waves
What type of surface is the best at absorbing and emitting infrared radiation?
Dark, Matt surfaces absorb the most infrared.
What surfaces are the best reflectors of infrared?
Light shiny surfaces
Why are the three states of matter?
Solid, liquid and gas
How are the particles in a solid arranged?
They are held next to each other, vibrating in their fixed positions
How are the particles in liquids arranged?
They move about randomly and at in contact with each other
How are the particles in a gas arranged?
They move are puns randomly and are far apart
What state of matter does conduction take place in?
Mainly solids. Liquids and gases are poor conductors
What happens when a solid is heated?
The particles gain kinetic energy and vibrate more, transferring the energy through the solid
What is an insulator?
A poor conductor.
Why are materials that trap air good insulators?
Because air is a poor conductor.
What is a fluid?
A liquid or a gas.
Define convection.
The circulation of a liquid or gas cause by heating it.
What happens when you heat a liquid or gas?
Heating a liquid or gas makes it expand, therefore becoming less dense so it rises and causes circulation.
Why doesn’t convection occur in solids?
Because the particles are held in fixed positions an are my able to flow
What is evaporation?
When a liquid turns into a gas
What is condensation?
When a gas turns into a liquid
Give two factors that effect the rate of evaporation.
Surface area
Temperature
Give two factors that effect the rate of condensation.
Surface area
Surface temperature
Give three factors that effect the rate of energy transfer.
Temperature difference
Shape
Surface area
Why does trapping air in small pockets minimise air transfer?
because convection currents can not be set up.
give three ways of minimising energy transfer out of a house.
-Fibreglass loft insulation
-double glazing
draught proofing
-cavity wall insulation
What does the U-value tell us?
how much energy per second passes through a material
What is an advantage of solar heat panels?
They don’t use fuel to heat water
why is fibreglass a good insulator?
It contains trapped air
