Approximately how many BTU's does it take to melt 1 pound of ice to water at 32ºF?

Melting ice into water at 32ºF requires a specific amount of energy known as the latent heat of fusion. For ice, this latent heat is approximately 144 BTUs for each pound. This energy does not change the temperature of the ice; it is used to break the molecular bonds that keep the ice solid.

The reason 144 BTUs is the correct amount is rooted in the physical properties of water and ice, specifically the energy required to facilitate the phase change without altering the temperature. Other values provided do not reflect the thermal energy needed for this phase transition, making them incorrect. In the context of thermodynamics and energy transfer in heating processes, understanding the significance of latent heat is crucial for calculating energy requirements in various applications, such as refrigeration and heating systems.