Which method would NOT speed up drying?

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

Answer: (D)

Drying happens when water molecules escape from a surface into the surrounding air, so the rate at which evaporation occurs determines how fast something dries. Any method that speeds up evaporation will shorten drying time.

A fan helps by moving air away from the surface, so water vapor is removed more quickly and a larger difference in vapor pressure is maintained, pushing more water to evaporate. Increasing temperature gives water molecules more energy to break free from the surface, and warm air can hold more water vapor, both boosting evaporation. A hairdryer combines warming the air with a directed breeze, which accelerates the evaporation process even more.

Using a catalyst, however, speeds up chemical reactions. Drying is a physical process (evaporation) and doesn’t involve a chemical reaction that a catalyst would accelerate. So a catalyst wouldn’t speed up drying.