Hooke's law and liquid pressure

PhysicsForces & DynamicsAges 15–16

Left: a spring of stiffness k holds a hanging mass m, stretching by Δl = mg/k; pull the mass down and release it to see it oscillate about equilibrium, with the F–Δl graph staying a straight line up to the elastic limit. Right: connected vessels hold a liquid of density ρ; drag the measuring point through depth h to see p = p₀ + ρgh, and that the liquid level is always the same in both branches.