Energy Transfer by Heating Flashcards
What is thermal conductivity?
The rate at which thermal energy is transferred through a material.
How does the rate of thermal conductivity effect the amount of energy transferred?
The higher the rate of thermal conductivity of a material, the more energy is transferred through it per second
What is an insulator?
A material that has a low thermal conductivity
What is specific heat capacity (SHC)?
The amount of energy needed to to change the temperature of 1kg of a substance by 10C
How do you measure SHC?
Measured in J/ kg 0C
What is the equation for finding the SHC of a material?
c = ΔE ÷ (m x Δθ)
What is a storage heater?
A device that has special bricks of material with a high SHC inside
What are solar panels?
Panels that absorb IR radiation from the sun and convert it into electricity
What is a cavity wall insulation?
A foam that is pumped in the space between the two layers of the wall of a house that reduces the rate of energy transfer through the outer walls of a house
What is double glazing?
Where you have two window panes with a layer of dry air or a vacuum between them that reduces the rate of energy transfer by conduction as dry air is a good insulator
How does putting aluminium foil behind radiators decrease thermal conductivity?
Reduces energy transfer by radiation as IR energy from the heater is reflected back into the room away from the wall
What is infrared radiation?
A type of radiation that shows how much heat is being given off in an area. The hotter the object, the more IR it gives off
What is the equation for energy transferred?
Energy transferred = mass x SHC x temp change ΔE = m x c x Δθ
What is black body radiation?
A perfect black body is an object that absorbs all of the radiation incident on it.
How does IR radiation effect the Earth’s temperature?
IR from the Sun can be reflected back into space from the Earth’s surface, absorbed by the Earth’s surface or absorbed by the Earth’s atmosphere.
IR can also be emitted from the Earth’s surface and from the Earth’s atmosphere into space.
