Final answer:
When energy is added to ice, the temperature does not increase initially because it is used to break the bonds between the water molecules and facilitate the phase change from solid to liquid. The temperature remains constant at the melting point until all the ice has melted.
Step-by-step explanation:
When energy is added to ice, the temperature does not initially increase because the added energy is used to break the bonds between the water molecules in the solid, allowing them to move around and become a liquid. This phase change from solid to liquid requires energy, but it does not result in a temperature increase. The temperature remains constant at the melting point until all the ice has melted. This is because the energy is being used exclusively to overcome the attractive forces that hold the solid together, rather than increasing the kinetic energy of the molecules.