Measure the angle inside the liquid The definition is easy to distort in a diagram. Always locate the tangent to the liquid surface and read the angle inside the liquid, not outside the drop or outside the tube.

Translate the angle into wetting behaviour Acute means the liquid wets the solid and climbs the wall, while obtuse means it does not wet the solid and the meniscus becomes convex.

Use standard examples as anchors Water-glass, water-silver, and mercury-glass are the common reference pairs in this OCR block, so memorise the sign of the angle before memorising the approximate values.

Keep the force-resultant picture ready The meniscus shape follows the resultant of adhesion and cohesion because the free surface adjusts perpendicular to that resultant. This explains the geometry instead of leaving it as a list.

Treat impurity and temperature changes as trend questions The OCR states that angle of contact decreases with increasing temperature, decreases with soluble impurities, and increases with partially soluble impurities. Those are common one-line objective checks.