Final answer:
When solid water gains energy, it goes through a phase change from solid to liquid, known as melting, where added heat breaks molecular bonds without raising temperature until all ice has melted.
Step-by-step explanation:
When solid water (ice) gains energy, it undergoes a phase change from solid to liquid, a process known as melting. Initially, as heat is added, the temperature of the ice increases until it reaches 0 °C, which is the melting point of ice. At this melting point, the energy being added does not continue to raise the temperature but is instead used to break the bonds between the water molecules, allowing the ice to change state from solid to liquid. This is described as the heat of fusion. Once all the ice has melted, any additional energy will start to raise the temperature of the liquid water.
In this process, no temperature change is observed until all the ice has melted, meaning a cup of soda and ice initially at 0 °C will stay at that temperature until all of the ice is melted. The energy transfer during this phase change is necessary to break molecular bonds and does not contribute to a temperature increase until the transition is complete.