How Does a Smoke Detector Work? | Smoke, Light, Alarm! Kids’ Song

What is that gray ribbon in the air? The bread stayed in the toaster too long. Smoke rides the air toward the ceiling. A white round detector waits up there. Through tiny slots, it enters the chamber. A tiny LED sends out a beam. Off to one side, a receiver waits like an eye. Smoke scatters light toward the eye. The receiver notices the change. Beep-beep-beep, the loud alarm warns us. Smoke, light, alarm—that's how it works. In clean air, the beam keeps going straight. It passes the receiver at the side. When smoke drifts into the dark chamber, its tiny particles scatter light. Some of that light reaches the waiting eye. Smoke scatters light toward the eye. The receiver notices the change. Beep-beep-beep, the loud alarm warns us. Smoke, light, alarm—that's how it works. The detector notices the light change. It starts the alarm: beep-beep-beep. Everyone at home hears the warning. Smoke scatters light toward the eye. The receiver notices the change. Beep-beep-beep, the loud alarm warns us. Smoke, light, alarm—that's how it works. Everyone heard the detector's warning. Smoke, light, alarm—that's how it works.