Why does paint dry and harden?
Show answer & explanation
Answer: Solvents evaporate away
Air pressure compresses paint — Wrong. Air pressure doesn't compress paint into solid. Drying happens when liquid solvents evaporate, leaving solid pigments and binders behind.
Solvents evaporate away ✓ — Correct! Paint contains pigments (color) suspended in solvents (water or oil-based liquids). When exposed to air, solvents evaporate, leaving behind solid pigments bound together by resins. Some paints also undergo oxidation (chemical hardening). That's why wet paint is liquid but dry paint is solid!
Pigments crystallize together — Wrong. Pigments don't crystallize—they're already solid particles. Paint hardens because the liquid solvent evaporates, leaving behind the solid pigment and binder that forms a hard film.