This document provides learning materials on gas pressure for A-level Physics students. It includes: 1) A review of Brownian motion and how it demonstrates gas molecules are in motion. 2) Learning objectives on defining pressure and using the kinetic model to explain gas pressure. 3) Exercises for students to define pressure, recall standard atmospheric pressure values, and use a practical investigation to qualitatively and quantitatively describe the relationship between gas particle motion, pressure and volume.