An oceanographic sensor probe is fully submerged at a depth of 50 metres in a freshwater reservoir. The same probe is then fully submerged at the same depth of 50 metres in a highly saline coastal bay, where the density of the water is significantly higher.
Explain why the probe experiences a different upthrust (buoyant force) in the coastal bay than in the freshwater reservoir.
54 exam-style questions on Edexcel GCSE Physics 15.2 Pressure in fluids, covering 15.2.1 Atmospheric pressure and height, 15.2.2 Pressure in fluids, 15.2.3 Pressure, force and area, 15.2.4 Pressure and depth, 15.2.5 Pressure in liquids: depth and density, 15.2.6 Upthrust, and 15.2.7 Floating and sinking. Each one has a worked solution and a mark scheme showing where the marks go.