Density and pressure
density = mass ÷ volume
pressure = force ÷ area
A 300 g block with volume 120 cm³ has density 300 ÷ 120 = 2.5 g/cm³. A 600 N crate on 0.2 m² presses with 600 ÷ 0.2 = 3000 N/m². A smaller area gives a bigger pressure.
Mixtures and units
To mix two liquids, find the total mass and the total volume first: densities do not average.
Area units square: 1 m² = 100 × 100 = 10,000 cm². So 3 N/cm² = 30,000 N/m². And 1 g/cm³ = 1000 kg/m³.