Final answer:
Investigation #1 is not an example of conduction; instead, it illustrates radiation as the sun's energy melts the ice cream without direct contact.
Step-by-step explanation:
The investigation that was not an example of conduction is Investigation #1. In this scenario, the radiation from the sun heats the ice cream without direct physical contact, which is different from conduction that requires contact between objects. The correct option is:
a) Investigation #1 is an example of radiation because the thermal energy from the Sun is traveling through space to heat the ice cream and cause it to melt.