Heating And Cooling Flashcards
How can heat be transferred?
Convection
Conduction
Radiation
Kinetic theory of a solid?
Arrangement of particles -close together in a regular pattern
Movement of particles-
Vibrate in fixed position
Kinetic theory of a liquid?
Arrangement of particles-
Close together but random pattern
Movement of particles-
Move around eachother
Kinetic theory of a gas
Arrangement of particles - far apart and random
Movement of particles-
Move quickly in any direction
Which states of matter cannot be compressed ?
Liquids and solids
What is a good conductor?
Metals
What do you call a poor conductor of heat?
Insulator
What happens in conduction (6 marks)
The ELECTRONS leave their ATOMS and become FREE ELECTRONS
the parts of the atoms left behind are now CHARGED METAL IONS
this vibrate continually
The hotter the metal , the more KINETIC ENERGY the vibrations have
The kinetic energy goes from the hot to cool parts of a metal by FREE ELECTRONS whilst colliding with IONS
What is a conductor?
Material through which energy is transferred easily
What is an insulator?
Material through which the speed of transfer of energy is reduced
What happens in convection currents?
Heat applied so particles gain energy
Fluid expands
Less dense particles rise to the top
More dense particles drop to the bottom
BOOM CONVECTION CURRENT
What is evaporation?
Liquid to gas
What is condensation?
Gas to liquid
What factors affect the rate of condensation and evaporation ?
Surface area of the liquid
If air is moving over the surface of a liquid
How does an animal reduce heat loss?
Have a small surface area to volume ratio
What is a u value?
Shows How effective of an insulator something is
What is the rule with u values ?
Lower the u value , the better the insulator
What do solar panels do? (4 marks)
Heat energy is taken from the sun
Cold water is pumped to the solar panel
The water is heated by the heat energy in the sun
This then returns to the tank
Advantages of solar panels?
Renuable
No pollution
Disadvantages of solar panels?
Don’t work at night
Only very hot in the summer
What is the difference between temperature and heat?
Temperature (*c) measures how hot something is
Heat (j) measures the amount of thermal energy in an object
What does temperature increase depend on?
Mass
Substance
Amount of energy transferred
More energy transferred means…
… Higher the temperature
What is specific heat capacity ?
Amount of thermal energy needed to raise the temperature of a 1kg substance by 1*c
