See what the students do not know and give them the information that they do not have. Expand on and discuss the different ideas for reinforcement. Controlled fire is one of humanity's best friends. Primitive people used fire for heating, cooking, turning clay into pottery, and light. Except for furnishing light, fire is used by people today for much the same things.
Fire also furnishes the energy for running steam engines and other machines.
It is used to separate metals from their ores and for many chemical processes. Uncontrolled fire is one of humanity's worst enemies. Fires have caused many deaths and billions of dollars in property damage in the United States. Some fires are brought about by natural causes. Lightning often starts forest fires.