Common Misconceptions
Part of Gas Pressure & Temperature · GCSE GCSE Physics revision
This common misconceptions covers Common Misconceptions within Gas Pressure & Temperature for GCSE Physics. Revise Gas Pressure & Temperature in Particle Model for GCSE Physics with 19 exam-style questions and 30 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 7 of 12 in this topic. Use this common misconceptions to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 7 of 12
Practice
19 questions
Recall
30 flashcards
⚠️ Common Misconceptions
Misconception 1: "Pressure increases because particles get bigger when heated"
Particles do not change size when heated. Pressure increases because the SAME particles move FASTER — they hit the walls more frequently and with more force. Size of particles is unchanged.
Misconception 2: "Pressure and temperature are linked using Celsius"
Gas law calculations MUST use Kelvin (absolute temperature), not Celsius. −273°C = 0 K. If you use Celsius, calculations will be completely wrong. Always convert: T(K) = T(°C) + 273.
Misconception 3: "Pressure in a liquid is the same at all depths"
Pressure in a liquid increases with depth (P = ρgh). This is why deep-sea divers face enormous pressures and submarines must have thick walls. Greater depth = more weight of liquid above = greater pressure.
Quick Check: Convert 27°C to Kelvin and explain why Kelvin must be used in gas pressure calculations.
27°C + 273 = 300 K. Kelvin must be used because the relationship between pressure and temperature (p ∝ T) only holds when using the absolute temperature scale. Kelvin starts at absolute zero (−273°C), where particles have minimum kinetic energy and pressure would theoretically be zero. Celsius is an arbitrary scale that doesn't start at zero kinetic energy.
Keep building this topic
Read this section alongside the surrounding pages in Gas Pressure & Temperature. That gives you the full topic sequence instead of a single isolated revision point.
Practice Questions for Gas Pressure & Temperature
A sealed gas container is heated. What happens to the pressure of the gas inside?
A sealed gas cylinder is heated. Explain, using particle theory, why the pressure of the gas increases when the temperature increases.
Quick Recall Flashcards
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