When a puddle of water evaporates on a sunny day, where does the energy required for evaporation primarily come from?

• A. The air pressure pushing down on the puddle
• B. The Sun's radiation heating the water
• C. The chemical bonds within the water molecules
• D. The Earth's internal geothermal energy

Answer: (B)

Verified step by step guidance

1. Understand the process of evaporation: it requires energy to convert liquid water into water vapor, which is called the heat of vaporization.
2. Identify the source of this energy: evaporation is an endothermic process, meaning it absorbs energy from the surroundings to overcome intermolecular forces in the liquid.
3. Consider the options given: air pressure pushing down does not supply energy; chemical bonds within water molecules are not broken during evaporation (only intermolecular forces are overcome); Earth's internal geothermal energy is generally not involved in surface evaporation.
4. Recognize that the primary source of energy for evaporation on a sunny day is the Sun's radiation, which heats the water and provides the necessary energy for molecules to escape into the vapor phase.
5. Summarize that the Sun's radiation increases the kinetic energy of water molecules, enabling evaporation to occur.