Smoke alarms are devices designed to detect smoke and alert occupants of a building to potential fire hazards. They work by using sensors that can identify smoke particles in the air. When smoke is detected, the alarm emits a loud sound to warn people nearby, giving them time to evacuate safely. There are different types of smoke alarms, including ionization and photoelectric models. Ionization smoke alarms are more responsive to fast-flaming fires, while photoelectric smoke alarms are better at detecting smoldering fires. Regular maintenance, such as testing and changing batteries, is essential for ensuring their effectiveness.