This document discusses the gas laws unit of an A-Level Physics course. It covers Boyle's law, which states that the pressure and volume of a gas are inversely proportional at a constant temperature. Students learn how to describe gases using properties like number of moles, mass, pressure, volume and temperature. Practical activities are described to investigate the effects of changing pressure on volume and of changing temperature on both volume and pressure of a gas. The objectives are to state Boyle's law and understand the relationships between these gas properties.