SCIENCE FORM 2 CHAPTER 9 (9.3)

CHAPTER 9:

Heat

9.3 PRINCIPLE OF EXPANSION &
CONTRACTION OF MATTER

9.3 PRINCIPLE OF EXPANSION & in solid
CONTRACTION OF MATTER

Gauge and
metal bar

When heated

• particles vibrate faster and move

further apart from one another
• Volume of solid increase because

solid expands

9.3 PRINCIPLE OF EXPANSION & in solid
CONTRACTION OF MATTER

Gauge and
metal bar

When cooled

• particles vibrate slower and move

closer to one another
• Volume of solid decrease because

solid contracts

9.3 PRINCIPLE OF EXPANSION & in liquid

CONTRACTION OF MATTER

When heated

• particles move faster and randomly
• Volume of liquid increase because

liquid expands

9.3 PRINCIPLE OF EXPANSION & in liquid

CONTRACTION OF MATTER

When cooled

• particles move slower and closer
• Volume of liquid decrease because

liquid contracts

9.3 PRINCIPLE OF EXPANSION & in gas

CONTRACTION OF MATTER

When heated

• particles move faster and randomly
• Volume of gas increase because gas

expands

9.3 PRINCIPLE OF EXPANSION & in gas

CONTRACTION OF MATTER

When cooled

• particles move slower and closer
• Volume of liquid decrease because

liquid contracts

THE USES OF EXPANSION
AND CONTRACTION

OF MATTER IN DAILY LIFE

THE USES OF EXPANSION AND CONTRACTION OF MATTER IN DAILY LIFE

Mercury in
thermometer
can expand
and contract

1. THERMOMETER

THE USES OF EXPANSION AND CONTRACTION OF MATTER IN DAILY LIFE

2. RAILWAY TRACKS
Small gaps between their rails
to enable them to expand in
hot weather

Without
gaps, the
tracks
will
buckle
and

THE USES OF EXPANSION AND CONTRACTION OF MATTER IN DAILY LIFE

3. STEEL BRIDGES

Built with rollers
and a gap on one

end

THE USES OF EXPANSION AND CONTRACTION OF MATTER IN DAILY LIFE

4. BIMETALLIC STRIP Copper
Iron
Used in devices that depend on
temperature regulation.

Eg: Iron and fire alarm system

Which one copper?
Which one iron?

FIRE ALARM SYSTEM

When the circuit is exposed to heat from a fire, the
copper stip will expand faster than the steel strip. This
cause the strip to bend towards the contact point. This
completes the circuit system and causes the alarm to ring