The document discusses different methods of energy transfer through heating processes. It explains that energy can be transferred through conduction, convection, and radiation. It also discusses factors that affect the rate of energy transfer such as surface area, material properties, and temperature differences. Key terms are defined related to different heating processes and energy transfer methods.

1. The transfer of energy by heating
processes and the factors
that affect the rate at which that
energy is transferred

2. Energy can be transferred from one place to another by work
or by heating processes. We need to
know how this energy is transferred and which heating
processes are most important in a particular
situation.

3. I can:
✓
compare ways in which energy is transferred in and
out of objects by heating and ways in which the
rates of these transfers can be varied
evaluate the design of everyday appliances that
transfer energy by heating, including economic
considerations
evaluate the effectiveness of different types of
material used for insulation, including U-values
and economic factors including payback time
evaluate different materials according to their
specific heat capacities.

4. Key words
Conduction
Convection
Radiation
Emit
Absorb
Conductor
Insulator
Kinetic theory
Evaporation
Condensation
Energy
Work
Transfer
U-values
Payback time
Specific heat capacity

5. Infrared radiation
a) All objects emit (give out) and absorb (take in) infrared
radiation.
If an object is a good emitter, it will also be a good absorber.
b) The hotter an object is the more infrared radiation it
radiates (gives out) in a given time.
If the object is cooler than its surroundings it will absorb more
heat than it emits, so it will warm up.
c) Dark, matt surfaces are good absorbers and good emitters
of infrared radiation.
d) Light, shiny surfaces are poor absorbers and poor emitters
of infrared radiation.
e) Light, shiny surfaces are good reflectors of infrared
radiation.

6. P1.1.2 Kinetic theory
a) The use of kinetic theory to explain the different states of
matter.
The diagram shows the difference between a solid, liquid and a
gas.

7. As a substance is heated the particles will vibrate
more and move about more.
In a solid the particles are arranged in a tight
pattern, they don’t have much energy and so only
vibrate a little
What will happen when a metal bar is heated?

8. In a solid the particles are arranged in a tight
pattern, they don’t have much energy and so only
vibrate a little
In a liquid the particles are close together, but can
move past each other.
In a gas the particles have much more energy than in
liquids or solids, they are free to move in any direction.
Heating gives the particles more energy; this will cause
solids to melt and liquids to boil.
b) The particles of solids, liquids and gases have
different amounts of energy.
In a liquid the particles are close together, but can
move past each other.

10. solid
gas
solid

11. P1.1.3 Energy transfer by heating
a) The transfer of energy by
conduction, convection, evaporation and
condensation involves particles,
and how this transfer takes place.

14. b) The factors that affect the rate of evaporation and
condensation.
Evaporation is when a liquid turns to a gas
Condensation is when a gas turns to a liquid.

15. c) The rate at which an object transfers energy by
heating depends on: surface area and volume
the material from which the object is made the
nature of the surface with which the object is in
contact.
d) The bigger the temperature difference between
an object and its surroundings, the faster the rate at
which energy is transferred by heating.

16. Conductors and insulators
Conduction occurs when particles vibrate and pass on
their energy to a neighbouring particle.
Materials with particles close together conduct heat
much faster then materials with large spaces
between particles.
Metals are good conductors because
of their free electrons.
The electrons are free to move around
inside the metal so they transfer the
energy very quickly to other particles.

17. Convection
As air warms up, it expands and so is less dense. It
will then rise. As it cools it becomes more dense
and so will sink.

18. Sea breezes are also caused by convection
currents:

19. conduction
convection
Traps lots of air [not heat]; air is a good insulator/ poor
conductor

21. Plastic/ glass walls
Vacuum
Insulating top
Silvering/ shiny on either wall

22. Transfer of energy by waves
Ions/ electrons gain kinetic energy
Energy is transferred to cooler parts by free electrons as they diffuse
through the metal and collide with ions

23. Water particles at the bottom are heated
The warm water expands (becomes less dense)
So the warm water rises and cold
water falls to take its place

24. Hot water rises [not heat rises]
because of convection currents
Inside is hotter than outsideHeat transfer by conductionSurround/cover/ insulate tank with good
insulator

25. Air is an insulator/ poor conductor
Convection stopped foam is an insulator/ poor
conductor