Which statement correctly describes glycerol's effect on bubble longevity (rephrased)?

• A. Glycerol binds with air to preserve bubbles.
• B. Glycerol adds scent to the bubbles.
• C. Glycerol adheres to water molecules to reduce evaporation.
• D. Glycerol makes bubbles heavier and sink.

Answer: (C)

Bubble longevity hinges on how fast water evaporates from the thin soap film. Glycerol helps by sticking to water and forming hydrogen bonds, which keeps water in the film longer and makes the film more viscous. This slows evaporation and reduces film thinning, so the bubble lasts longer. It doesn’t preserve bubbles by binding with air, add scent, or make bubbles sink—those ideas don’t explain the observed increase in life.