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 (physics only). Each one has a worked solution and a mark scheme showing where the marks go.