Why is a steam burn typically more severe than a hot water burn?

• A. Steam is always at a higher temperature than boiling water.
• B. Steam releases additional energy as it condenses on the skin, transferring both heat and the latent heat of vaporization.
• C. Hot water evaporates quickly, reducing the amount of heat transferred to the skin.
• D. Steam contains dissolved chemicals that make burns worse.

Answer: (B)

Verified step by step guidance

1. Understand the concept of phase change and latent heat: When steam condenses into liquid water on the skin, it releases the latent heat of vaporization, which is the energy required to convert liquid to gas without changing temperature.
2. Recognize that both hot water and steam can be at the same temperature (e.g., 100°C at atmospheric pressure), so temperature alone does not explain the severity difference.
3. Analyze the heat transfer process: Steam releases not only its sensible heat (heat due to temperature) but also the latent heat when it condenses, transferring more total energy to the skin compared to hot water at the same temperature.
4. Consider that hot water loses heat as it cools down and evaporates, but it does not release latent heat to the skin because it is already in the liquid phase.
5. Conclude that the additional energy from the latent heat of vaporization released by steam condensation causes more severe burns than hot water at the same temperature.