P2 Energy transfer by heating- Physics Paper 1 Flashcards
What does an insulator do?
Slows down the rate of transfer of heat
Why can metals and graphite conduct heat?
Because of their de-localised electrons
What does a good conductor of heat allow and what does a poor conductor of heat allow?
A good conductor of heat allows a quick transfer of thermal energy through itself. Whereas a poor conductor of thermal energy only allows heat to be transferred slowly.
How do metals conduct heat?
When a metal is heated, the kinetic energy store of the de-localised electrons increases. These electrons are free to move and they transfer energy by jostling ions in the metal. This is why heat transfer in metals is very efficient.
Why are insulators poor conductors of heat?
Because they don’t have de-localised electrons
What is an independent variable?
Something that can change
What is the dependent variable?
The thing that you measure to see if it changes
What is the control variable?
The thing that you keep the same
What is conduction?
The transfer of heat through a material by transferring kinetic energy from one particle to another.
Describe what thermal conductivity indicates
How much thermal energy is transferred every second through a material. The higher the thermal conductivity, the quicker heat is transferred to the substance.
what are the factors that affect the rate of energy transfer in a material?
- Temperature difference across the material.
- Thickness of materials
- Thermal conductivity
How does temperature difference across a material affect energy transfer?
The bigger the temperature difference, the faster the rate of energy transfer.
How does the thickness of a material affect energy transfer?
The thicker the material, the longer it takes the energy to transfer
What is the specific heat capacity?
The amount of energy required to raise the temperature of 1kg of a substance by 1 degrees celcius.
What is the equation for change in thermal energy?
change in thermal energy = mass x SHC x chage in temperature
