sentence2_structure: Heat transfer<>by<>conduction$$$Heat transfer<>by conduction occurs<>molecules$$$Heat transfer<>by conduction occurs molecules collide with<>other molecules$$$conduction<>occurs<>molecules$$$conduction<>occurs molecules collide with<>other molecules$$$molecules<>collide with<>other molecules
sentence1: Conduction The flow of heat by conduction occurs via collisions between atoms and molecules in the substance and the subsequent transfer of kinetic energy.
sentence2: Heat transfer by conduction occurs molecules collide with other molecules.
question: Heat transfer by conduction occurs when molecules