4.3.4—The equation ∆p = ρg∆h

Between two points separated vertically by ∆h in a fluid of uniform density, the pressure difference is ∆p=ρg∆h.

Only the vertical separation matters. Include a sign or state which point is deeper; pressure increases downward.

A 0.50 m level difference in oil of density 800 kg m⁻³ gives ∆p≈3.92 kPa at g=9.8 m s⁻².

Do not use the total container height when comparing two points, and do not reverse the pressure order with the depth sign.