Class 9 Science — Chapter 11: SOUND

What you'll learn

• ▸Production of Sound by Vibrating Objects
• ▸Propagation of Sound and the Role of a Medium
• ▸Compressions and Rarefactions
• ▸Sound as a Longitudinal Wave
• ▸Graphical Representation of a Sound Wave
• ▸Characteristics of a Wave: Wavelength and Frequency

Chapter Summary

--- PAGE 1 --- Chapter 11 0964CH12 SOUND Everyday we hear sounds from various sources like humans, birds, bells, machines, vehicles, televisions, radios etc. Sound is a form of energy which produces a sensation of hearing in our ears. There are also other forms of energy like mechanical energy, light energy, etc. We have talked about mechanical energy in the previous chapters. You have been taught about conservation of energy, which states that we can neither create nor destroy energy. We can just change it from one form to another. When you clap, a sound is produced. Can you produce sound without utilising your energy? Which form of energy did you use to produce sound? In this chapter we are going to learn how sound is produced and how it is transmitted through a medium and received by our ears. 11.1 Production of Sound Activity _______________ 11.1 • Take a tuning fork and set it vibrating by striking its prong on a rubber pad. Bring it near your ear. • Do you hear any sou…

Practice Questions from this Chapter

Tap "Get Solution" on any question to ask our AI tutor.

1. Describe how instruments make music. Get Solution →
2. Explain sound travel in space. Get Solution →
3. Compare human and animal hearing. Get Solution →
4. According to the text, what is sound? Get Solution →
5. What is the fundamental requirement for an object to produce sound? Get Solution →
6. What is the matter or substance through which sound is transmitted called? Get Solution →
7. In a sound wave, what is a region of high pressure called? Get Solution →
8. What is the SI unit for frequency? Get Solution →

Did you know?

• 💡 Whales use extremely low-frequency sounds to communicate across entire oceans.
• 💡 A famous bridge once collapsed because wind vibrations matched its natural frequency.
• 💡 Space is silent because sound waves need a medium to travel, and space is mostly empty.
• 💡 The loudest sound ever recorded was a volcanic eruption, heard 3,000 miles away.
• 💡 Bats navigate and hunt by sending out high-pitched sounds and listening for echoes.

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