AQA GCSE Combined Science: Trilogy Physics Paper 1 (Higher), 2023: Question 6

✅ Correct answer

• The air particles move faster / have more kinetic energy.
• They collide more frequently with the walls of the chamber, or with more force.
• So the pressure increases.

💡 Key knowledge

• Heating a gas increases the particles’ kinetic energy.
• Faster particles hit the container walls more often.
• More frequent or stronger collisions mean higher pressure.

🧠 Exam technique

• This is a 3-mark explanation: write a chain of cause and effect.
• Use physics language: faster → more collisions → higher pressure .
• Make sure you actually state the pressure increases.

❌ Common errors

• Saying only “temperature increases” without explaining pressure.
• Writing that particles “expand” — particles do not expand.
• Confusing pressure with temperature.

✅ Correct answer

Metals have a higher thermal conductivity, so thermal energy is transferred more quickly from the hot coffee to the air in the chamber.

💡 Key knowledge

• Metals are good conductors of thermal energy.
• Plastic is a poor conductor / insulator.
• A good conductor helps the air warm up faster.

🧠 Exam technique

• Use the phrase thermal conductivity for full marks.
• Link the material property to the effect: faster energy transfer to the air.

❌ Common errors

• Just saying “metal is stronger” — that does not answer the question.
• Saying “metal is hotter” instead of explaining heat transfer.
• Forgetting to mention that the air must heat up quickly.

✅ Correct answer

A low specific heat capacity.

💡 Key knowledge

• Specific heat capacity is the energy needed to raise 1 kg of a substance by 1 °C.
• A low specific heat capacity means temperature changes quickly for a small energy change.

🧠 Exam technique

• For a 1-mark recall question, the exact term is enough.
• Use specific heat capacity, not “heat content” or “heat energy”.

❌ Common errors

• Saying “low density” — that is not the answer here.
• Giving a long explanation but missing the key term.

✅ Correct answer

• Lubricate the device / wheel.
• Use hotter coffee.
• Decrease the temperature of the surroundings.

💡 Key knowledge

• Faster heating increases pressure more quickly.
• Reducing friction lets the wheel spin more easily.
• Less heat loss to the surroundings helps the air warm up faster.

🧠 Exam technique

• Only one suggestion is needed.
• If you choose “use hotter coffee”, make it clear this means a bigger temperature difference / faster heating.

❌ Common errors

• Vague answers like “make it better” or “change the design”.
• Suggesting something unrelated to pressure or friction.

📐 Step-by-step calculation

1. Find the mass using density:
   density = mass / volume
2. Rearrange:
   mass = density × volume
3. Substitute values:
   mass = 1.1 × 10³ × 1.9 × 10⁻⁴
4. Calculate:
   mass = 0.209 kg
5. Use E = m c Δθ
   with E = 15 000 J , m = 0.209 kg , c = 4200 J/kg °C
6. Rearrange:
   Δθ = E / (m c)
7. Substitute:
   Δθ = 15 000 / (0.209 × 4200)
8. Calculate temperature decrease:
   Δθ ≈ 17.1 °C
9. Final temperature:
   76 − 17.1 = 58.9 °C
10. Rounded final answer:
    59 °C

✅ Correct answer

Final temperature of the coffee = 59 °C

🧠 Exam technique

• Show the equation used, then rearrange it clearly.
• Convert 15 kJ to 15 000 J.
• Use the correct unit for mass: kg.
• Give the final answer to a sensible number of significant figures.
• Because the coffee is losing energy, the temperature must go down.

❌ Common errors

• Forgetting to convert kJ to J.
• Using volume directly in the heating equation instead of first finding mass.
• Using E = m c θ incorrectly without the change in temperature.
• Writing 76 + 17.1 instead of subtracting.
• Dropping the unit or writing an answer with the wrong unit.

💡 Best features of full-mark answers

• Used the correct science vocabulary.
• Linked ideas in the right order.
• Gave a clear final conclusion.
• Showed the full calculation method with units.

🧠 Examiner-style advice

• For explanation questions, think: cause → effect → conclusion.
• For calculations, always write the equation first.
• If a question says “suggest one way”, one clear idea is enough.