Question

(a) Solids, liquids, and gases have different properties.

Draw two lines from each state of matter to link to two correct properties of matter.

You may draw lines to each property of matter once, more than once, or not at all.

One line has been drawn for you.

▶️Answer/Explanation

Solid: Difficult to compress and fixed shape.
Liquid: Difficult to compress and able to flow.
Gas: Easily compressed and able to flow.

(b) When a liquid is heated, it expands.

(i) Describe how the structure of a liquid-in-glass thermometer is designed to make use of this property.

(ii) When a liquid is heated to a high enough temperature, it starts to boil. State the meaning of the term boiling point.

▶️Answer/Explanation

(i) The liquid is held in a narrow tube. As it is heated, the liquid expands and rises up the tube. The temperature is read from the scale marked on the tube.
(ii) The temperature at which a liquid turns into a gas.

(c) Some materials conduct thermal energy well, and other materials are better thermal insulators.

Complete Table 6.1 by placing a tick (✓) in the correct column for each material.

Material	Thermal Conductor	Thermal Insulator
Aluminium
Copper
Plastic
Steel
Wool

▶️Answer/Explanation

Aluminium: Thermal Conductor (✓)
Copper: Thermal Conductor (✓)
Plastic: Thermal Insulator (✓)
Steel: Thermal Conductor (✓)
Wool: Thermal Insulator (✓)

(d) State the name of the process that transfers thermal energy from the Sun through the vacuum of space.

▶️Answer/Explanation

Radiation.

(e) (i) Complete the sentence to describe sound waves.

Sound waves transfer …… without transferring matter. 

(ii) State the approximate range of audible frequencies for a healthy human ear.

(iii) The pitch and loudness of a sound wave are increased.

State how the amplitude and the frequency of the sound wave change.

▶️Answer/Explanation

(i) Energy.
(ii) From 20 Hz to 20,000 Hz.
(iii) Amplitude increases and frequency increases.