Question 6
6.1
a. Energy is the ability to do work and energy transfer is the movement of energy from one place to
another. [1]
b. The sun is categorised under thermal system
c. Thermal energy is energy produced by heat e.g. when body is warmed by warm water in a bath.
d. The sun has chemical potential energy
e. It is cold in winter, so people sit inside in direct sunlight to warm their body by heat from the
sun.
6.2
a.
b.
c.
d.
e.
f.
Conduction – is the heat transfer through contact of objects.
Radiation is the heat transfer without a medium such as air or liquid
Convection is the heat transfer through liquid and gases
Insulator is the material that does not transfer heat
Convection is the circular movement of fluids cause by convection
Conductor is a material that transfers heat well
Question 7
7.1
1. This is because black material absorbs heat from the sun more than white material does.
2. Black material absorbs more heat energy than silver materials do. Shiny, silver, material
reflects light and heat.
3. Hot air rises, so the air around the heater gets warm and rises to the ceiling. Cold air
sinks down to be heated by the heater. And rises up until the room is filled with warm
air. This kind of heat energy transfer is called convection
4. The base of cooking pots conduct heat from the stove and transfer it to all parts of the
pot. If the handle was not made a material that is poor conductor of heat, like wood or
plastic, it would be so hot that you could not be able to touch it.
5. A black car would absorb heat and would be far hotter to transfer to travel in, than a
lighter coloured car
7.2
Question 8
1.
2.
3.
4.
5.
C- air
A- coal
B- potential
E- biofuel
D- vacuum