Which method would NOT speed up drying?

• A. Using a fan
• B. Increasing temperature
• C. Using a catalyst
• D. Using a hairdryer

Answer: (C)

Drying is all about evaporation: water molecules escape from the surface and enter the air. You speed that up by removing the water vapor near the surface and by giving water molecules more energy to escape. A fan or a hairdryer moves air over the surface, carrying away the evaporated water so the surface isn’t surrounded by its own vapor. Increasing the temperature raises the water molecules’ kinetic energy, making it easier for them to break free into the air. Both of these methods actively boost evaporation and thus speed drying.

Using a catalyst won’t help here because a catalyst speeds up a chemical reaction, not the physical process of evaporation. Evaporation is a phase change, not a chemical change, so a catalyst doesn’t alter its rate.