Students' explanations related energy to fuel or sources of generating fire and electricity. It seemed that they considered fuel or fire as symbols of energy. They usually explained that cards of fish, a boy running, a gas station, and dam did not relate to energy. They thought that those cards related to energy only when it could generate fire or source of generating fire and electricity. Moddaeng (Grade 5) clearly stated that the fish related to energy when people use fire to cook.