Air flow enhances evaporation by removing water vapor Steps:

• Evaporation rate depends on surface area, temperature, humidity, and air movement over the liquid.
• In this setup, the hairdryer provides air movement to carry away humid air above the water surface.
• Evaluate options: changes to water amount (B, C) don't affect key factors like air flow or surface area.
• Identify the option that directly improves air movement in the described experiment.

Why A is correct:

• Increasing air speed accelerates the removal of saturated air, steepening the concentration gradient of water vapor and increasing the evaporation rate per Fick's law of diffusion.

Why the others are wrong:

• B: Decreasing mass leaves surface area and air flow unchanged, so rate stays the same.
• C: Increasing volume keeps surface area constant in the same beaker, so rate unchanged.
• D: Wider beaker increases surface area but changes the setup, potentially reducing effective air coverage from the hairdryer.

Final answer: A