One common way to evaluate surface tension and wetting is by measuring contact angles.

cosθ = ​(γSG​−γSL)/γLG

Based on Young’s equation, the contact angle theta (θ) reflects the balance of interfacial energies between the solid/gas (γSG), solid/liquid (γSL), and liquid/gas (γLG) interfaces.  In simple terms, the contact angle indicates how well a liquid spreads on a surface: lower contact angles mean better wetting, while higher angles indicate poorer spreading.

This concept is widely used in coatings, inks, and adhesives to understand how liquids interact with different substrates.​