Science

Echo and reverberation

In this Class 9 Science topic from “Sound Waves: Characteristics and Applications,” students learn how sound reflects from surfaces and produces an echo when the reflected sound is heard separately from the original. They distinguish echo from reverberation, in which reflected sounds persist and overlap because of repeated reflections. The topic explains time delay, the effect of distance and surface materials, and the role of sound absorption and reflection in classrooms, auditoriums, recording studios, sonar, and everyday communication.