Fluid - GCSE Physics Definition

In the context of GCSE Physics, a 'fluid' is a substance that can flow and take the shape of its container. Both liquids and gases are fluids. Unlike solids, fluids do not have a fixed shape, allowing them to easily conform to the geometry of any vessel they occupy. The particles in a fluid are free to move around, which accounts for their ability to change shape and flow. Key properties of fluids include pressure, density, and compressibility, all of which play a crucial role in understanding fluid behaviour in various physical contexts, such as buoyancy.