Heat transfer Flashcards
What is temperature?
The measure of how hot or cold an object is
The average kinetic energy of the particles in a substance
What is the unit of temperature?
º C
degrees Celsius
What is heat?
A form of energy
What is the unit of heat?
J or kJ
Joules or kiloJoules
Why do substances at high temperatures “cool down”?
They lose heat to the colder surroundings
Why does the temperature of a small volume of water drop more quickly than a large volume?
The larger volume has much more heat energy and it takes longer to transfer that to the surroundings
In which direction is heat transferred?
What are the 3 ways that heat can be transferred?
- conduction
- convection
- radiation
What is a fluid?
A liquid or a gas
What does density depend on?
Why are metals such good conductors of heat?
Particles are close together and can pass energy through vibrations
Electrons can move and transfer heat quickly
Describe the relationship betwen density and whether a fluid will rise or fall
Convection currents in liquids
Convection current from radiator
Whys is freezer compartment at top of fridge?
Why is it windy at seaside?
How do gliders use thermals to fly?
Which experiment shows convection currents in liquids?
What is conduction?
The movement of heat through particles that are touching each other transferring energy as they vibrate more.
What is a thermal conductor?
A material which allows heat to pass through it
What is a thermal insulator?
A material that does not allow heat to pass through it
What is thermal radiation?
The transfer of heat energy by electromagnetic waves. It doesn’t involve particles
How does heat from sun reach Earth?
Which colours absorb and reflect thermal radiation?
Dark absorbs
Shiny and bright reflect
