Measure mass with a balance and determine volume using a suitable method. For a regular solid, calculate volume from measured dimensions; for an irregular solid, use displaced liquid volume. For a liquid, subtract the empty container’s mass and read the measuring cylinder at eye level; use ρ = m/V. Example: Find density of an 80 g stone displacing 32 cm³. Density = 80/32 = 2.5 g/cm³. Rearrange the relationship before substituting if a different quantity is required. Give a reason. Compare cases.