Class 9 Science Chapter 10, Sound Waves: Characteristics and Applications, starts from sound as a form of energy and asks which energy turns into it and how it reaches our ears. It covers the production and propagation of sound, its wave properties, echo and reverberation, and ultrasound and infrasound.
What Class 9 Science Chapter 10 Covers
10.1 and 10.2 Production and Propagation use the tuning fork and show that sound needs a medium.
10.3 to 10.5 Sound Waves describe sound as a wave, its energy, and its graphical representation.
10.6 Characteristics of a Sound Wave cover wavelength, frequency and time period, amplitude and intensity, the speed of sound, and how humans perceive sound.
10.7 and 10.8 Reflection and Beyond Hearing explain echo and reverberation, then ultrasonic and infrasonic waves and echolocation.
Exercises in Chapter 10
- Revise, Reflect, Refine numericals on wavelength, frequency and speed of sound, and echo distance.
Read Class 9 Science Chapter 10 Online
More Chapters
- Previous: Chapter 9: Atomic Foundations of Matter
- Next: Chapter 11: Reproduction: How Life Continues
- Hindi medium: Class 9 Science Chapter 10 PDF in Hindi (Anveshan)
- All Science chapters and the other Class 9 books: Class 9 NCERT books 2026-27
FAQ
What is the difference between echo and reverberation?
An echo is a distinct repeat of a sound heard after reflection from a distant surface. Reverberation is the persistence of sound from many quick reflections, as in a large hall.
What is echolocation?
Finding objects by sending out ultrasonic sounds and listening for their echoes, as bats and dolphins do. It is in section 10.8.1.