Incomplete question. Answered from a general science perspective.
Answer:
a physical change
Step-by-step explanation:
It is important that to remember that when the ice cream melts as a result of the heat from the sun, the chemical elements that were mixed together to form the tasteful ice do not change, rather only the physical state of the ice cream changes.
For example, rather than being in mostly solid form, because of the hot temperature of the day, it becomes a liquid (which is rightly a physical change).