A smoke alarm is a safety device that detects smoke in the air, alerting people to potential fires. It usually makes a loud beeping sound when it senses smoke, giving you time to escape or take action. Most homes have at least one smoke alarm, often placed on ceilings or high on walls, where smoke rises first. There are different types of smoke alarms, including ionization and photoelectric models. Ionization alarms are better at detecting fast-flaming fires, while photoelectric alarms are more effective for smoldering fires. Regularly testing and changing the batteries in your smoke alarm can help keep your home safe.