How solids, liquids and gases expand when heated, the kinetic-theory explanation, the problems caused by expansion, and applications such as the bimetallic strip and thermostat.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
Railway tracks have small gaps and telephone wires sag in summer. Both are the physics of expansion at work.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Heat a bimetallic strip and see why it bends.
Copy these into your notebook in your own words — that is how they stick.
Increase in size when heated; particles move/vibrate more and push further apart.
Gases > liquids > solids.
Railway tracks, bridges, power lines, roofs, glass, carbonated bottles.
Gaps and rollers allow room for expansion.
Hot water: the metal lid expands more than the glass.
Two metals joined; the metal that expands more is on the outside of the bend.
The bending strip opens or closes a circuit.
The particles themselves do not expand.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Physics Arcade.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (15 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [15 marks]
A steel railway line is laid in sections with small gaps between them. A bimetallic strip is used in an electric iron.
(a) (a) Use the kinetic theory to explain why a steel rail expands when it is heated. [3]
(b) (b) Explain why gaps are left between sections of rail. [2]
(c) (c) State two other examples where expansion must be allowed for. [2]
(d) (d) Describe the construction of a bimetallic strip. [2]
(e) (e) Explain how a bimetallic strip bends when heated and cut off the supply in an iron. [4]
(f) (f) State one advantage and one disadvantage of the expansion of a liquid in a thermometer. [2]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.