4.5 Forces- pressure

Unit Summary

Understanding pressure is essential to grasping how forces are distributed across surfaces and within fluids. In AQA GCSE Physics Unit 4.5, students explore how pressure in solids, liquids, and gases affects systems ranging from the atmosphere to hydraulics. Key topics include pressure in fluids, atmospheric pressure, upthrust, and the transmission of pressure in liquids, all of which build a foundational understanding of how forces operate in real-world contexts such as diving, flying, weather systems, and hydraulic machines.

This unit aligns closely with the AQA GCSE Physics specification and builds on prior learning from earlier topics such as forces, density, and particle theory. Students are expected to apply their knowledge of force and area to understand pressure equations and extend this to consider depth and density in fluids. These concepts help students move from basic mechanical principles to more complex applications in fluid dynamics.

Both substantive knowledge (scientific content) and disciplinary knowledge (working scientifically) are carefully embedded throughout the unit. Students carry out investigations into the relationship between force, area, and pressure, using practical work to develop skills in measuring, calculating, and evaluating. The unit encourages students to interpret graphs, handle data confidently, and link theoretical concepts to observable phenomena such as why ears pop at altitude.

Prior knowledge is systematically reinforced with scaffolding and structured practice. Through worked examples, low-stakes quizzes, and practical applications, students deepen their understanding of pressure and its role in diverse physical systems—developing the confidence to apply physics in both examination and everyday contexts.

At Developing Experts, we are committed to supporting schools in delivering the National Curriculum while also broadening students’ aspirations. Our curriculum is designed to challenge students by connecting classroom learning to real-world applications. The study of pressure is not just theoretical—it has practical relevance in areas such as aviation, deep-sea exploration, meteorology, medicine, and hydraulics. By exploring these applications, students gain insight into how scientific principles like fluid pressure, upthrust, and atmospheric changes shape the technology and systems we rely on every day—from aircraft cabins to syringes and weather forecasting.