This definitions covers Key Definitions 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 6 of 12 in this topic. Make sure you can use the exact wording confidently, because definition marks are often lost through vague language.
📖 Key Definitions
Gas pressure: The force per unit area exerted by gas particles colliding with container walls. Units: Pascals (Pa) or N/m².
Absolute zero (0 K): The theoretical minimum temperature (−273°C) at which particles have minimum kinetic energy and gas pressure would be zero.
Kelvin (K): The SI unit of absolute temperature. T(K) = T(°C) + 273. Used in gas law calculations.
Upthrust: The upward force on an object submerged in a fluid, equal to the weight of fluid displaced. If upthrust ≥ weight, the object floats.
Atmospheric pressure: The pressure exerted by the atmosphere on objects at Earth's surface, approximately 100,000 Pa (100 kPa). Decreases with altitude as there is less air above.
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.