Year 9 Science · Unit 3 · Lesson 10
Foundation Worksheet
Learning Goals
Fill the gap
Choose the correct word from the word bank to complete the passage about why railway tracks have gaps. Two words in the bank are distractors, you will not use them.
When metal railway tracks are heated by the sun, the energy causes the particles inside the metal to more vigorously. Because each pushes against its neighbours, the overall track undergoes it gets slightly longer. In cold weather the particles slow down and the track will , becoming shorter. Engineers include a small gap at each expansion so that the track is free to expand in summer without buckling. A strip, which bends when heated, is used in thermostats to control temperature automatically.
True or False? Fix the false ones
Circle T or F for each statement. If the statement is false, rewrite it correctly on the line below.
Liquids expand more than gases when heated by the same temperature rise.
Correct it:
All materials expand at exactly the same rate when heated by 1°C.
Correct it:
Expansion joints in bridges allow the structure to expand and contract safely without cracking.
Correct it:
Thermal expansion occurs because particles get physically larger when they absorb heat energy.
Correct it:
1. Use particle theory to explain why a metal railway track expands on a hot summer day. Mention what the particles do when temperature increases.
2. A bimetallic strip is made by bonding two different metals together. Why does the strip bend when it is heated?
Wrap Up
In one sentence, what was the main idea of this lesson?