Thermal physics

Gas laws

EquationP₁V₁ = P₂V₂constant T, n

Compression (constant T)

Adjust parameters

Volume4.0 L
Temperature (constant)300 K
P = 62.4 kPa

P–V graph

Hyperbolic isotherm. Yellow dot = current state.

Real world

  • 🤿Scuba — gas in lungs expands as diver ascends.
  • 🩺Breathing — diaphragm lowers volume to draw air in.
  • 💉Syringes — reduced pressure draws in fluid.

Curriculum

WAECNECOIGCSESATJUPEB

📋 Teacher notes

  • Boyle's Law: at constant T, pressure and volume are inversely proportional — P₁V₁ = P₂V₂.
  • The P–V graph is a hyperbola. Each curve (isotherm) represents a different temperature.
  • Higher temperature isotherms sit above lower ones — more energy means higher pressure at same volume.
  • Real gases deviate from this at very high pressures or near condensation.
  • Ask: what happens to particles when volume decreases? Why does pressure increase?

✏️ Exercises