Primary 5 · Science · Energy: Heat & Temperature
Energy: Heat & Temperature questions for Primary 5 Science
10 questions to work through online, 2 of them written out the way the paper asks. Answer and you get the working straight away, then a score at the end. No sign-up, and you can retake it as often as you like.
- Reading a cooling curve
- Expansion and contraction
- Comparing amounts of heat
- Reading a thermometer
- Speeding up cooling
- Reasoning about expansion
- Naming a change
- Applying the ideas
Same picture as the question above.
| Container | Volume of water (ml) | Starting temperature (°C) |
|---|---|---|
| P | 100 | 80 |
| Q | 500 | 80 |
| R | 100 | 40 |
Answers and explanations for all 10 questions
Every answer with the reasoning behind it. Worth reading after you have tried the set — or on its own, if you are a parent marking it.
In the graph above, why does the line level off rather than continue falling?
Answer: The water has cooled to room temperature, so no more heat flows out of it.
Heat flows while there is a temperature difference. Once the water reaches the room's 20 °C there is no difference left, so the cooling stops.
According to the graph, when did the water lose heat fastest?
Answer: at the very beginning
The steeper the line, the faster the cooling. It is steepest right at the start, when the water is hottest and the difference from the room is greatest.
Which two of these happen because materials expand when heated?
Answer: A and B only
Heated wires get longer and sag; a heated metal lid gets slightly larger and lets go of the jar. Melting and evaporating are different things entirely.
Based on the table above, which container holds the most heat?
Answer: Q
Temperature is how hot; heat is how much energy altogether. P and Q are equally hot, but Q holds five times as much water, so it holds far more heat.
Based on the thermometers shown above, what is the difference between the two readings?
Answer: 25 °C
55 °C minus 30 °C leaves a difference of 25 °C.
Which two of these would make a cup of hot soup cool faster?
Answer: A and B only
A wide bowl exposes far more surface to the air, and a metal spoon conducts heat out and stirs the hot soup to the surface. Lids and towels do the opposite.
Why are small gaps left between the sections of a long concrete bridge?
Answer: so the concrete has room to expand on hot days without buckling
Concrete expands when it warms. Without gaps to expand into, the sections would press against each other hard enough to crack or buckle.
A metal ball is heated and no longer fits through a ring it passed through easily when cold. What has happened to the ball?
Answer: expanded
The ball has expanded, so it is slightly too large for the ring.
The same metal ball is cooled in iced water and now passes through the ring more loosely than before. What has happened to the ball?
Answer: contracted
On cooling the ball has contracted, so it is slightly smaller than before.
A cold drink left on a table in a warm room slowly reaches room temperature. What is the lowest temperature the room could then be?
Answer: the same as the drink's final temperature
Heat flows until the two are equal and then stops. Where the drink settles is exactly the room's temperature.