10. SOUND

10. SOUND

  • 10

    Sound

    This section explores the nature of sound, its production through vibrations, and how sound travels through various mediums.

  • 10.1

    Sound Is Produced By A Vibrating Body

    This section explores how sound is produced by vibrating bodies, the role of vibrations in sound generation, and how sound is perceived.

  • 10.2

    Sound Produced By Humans

    Sound in humans is produced by vibrations in the vocal cords located in the larynx.

  • 10.3

    Sound Needs A Medium For Propagation

    This section discusses how sound requires a medium, such as air, liquid, or solid, to travel and explains through experiments how sound behaves in various environments.

  • 10.4

    We Hear Sound Through Our Ears

    This section explains how sound is heard through the structure and function of the ear, emphasizing the role of the eardrum and sound vibrations.

  • 10.5

    Amplitude, Time Period And Frequency Of A Vibration

    This section discusses sound production through vibrations, focusing on amplitude, time period, and frequency.

  • 10.6

    Audible And Inaudible Sounds

    This section explores the range of sound frequencies detectable by the human ear, defining audible sounds as those between 20 Hz to 20,000 Hz, and highlighting inaudible sounds beyond these limits.

  • 10.7

    Noise And Music

    The section discusses the differences between pleasant and unpleasant sounds, identifying musical sounds as pleasing and noise as unpleasant.

  • 10.8

    Noise Pollution

    Noise pollution is the presence of excessive or unwanted sounds in the environment, which can cause various health issues.

  • 10.8.1

    What Are The Harms Of Noise Pollution?

    Noise pollution can lead to various health issues, including lack of sleep and hypertension.

  • 10.8.2

    Measures To Limit Noise Pollution

    This section discusses the various measures that can be taken to reduce noise pollution.

  • 10.9

    Hearing Impairment

    This section discusses the nature of hearing impairment, its causes, and the importance of communication methods like sign language for those affected.

  • 10.10

    Keywords

    This section outlines the fundamental concepts related to sound, including its properties and how it is perceived.

  • 10.11

    What You Have Learnt

    This section summarizes key concepts about sound, including its production, propagation, and effects.

  • 10.12

    Exercises

    This section contains a variety of exercises designed to reinforce the concepts related to sound, its production, and propagation, including activities and theoretical questions.

  • 10.13

    Extended Learning — Activities And Projects

    This section encourages students to actively explore the concept of sound through various activities and projects.

    • Key Summary

    Sound is produced by vibrating objects, and it travels through various mediums such as gases, liquids, and solids. The process of hearing involves the eardrum sensing vibrations, which are then communicated to the brain. Loudness and pitch are determined by the amplitude and frequency of the sound respectively, with excess noise contributing to pollution and potential health issues.

    Key Takeaways

    • Sound is produced by vibrating objects.
    • In human beings, the vibration of the vocal cords produces sound.
    • Sound travels through a medium (gas, liquid or solid). It cannot travel in vacuum.
    • The eardrum senses the vibrations of sound, sending signals to the brain.
    • The frequency of oscillation is expressed in hertz (Hz).
    • Larger amplitude means louder sound, whereas higher frequency results in higher pitch.
    • Unpleasant sounds are termed noise.
    • Noise pollution may pose health problems for human beings.
    • Measures should be taken to minimize noise pollution.

    Key Concepts

    • Vibration: The to and fro motion of an object that produces sound.
    • Eardrum: A thin stretched membrane that vibrates when sound waves hit it, allowing us to hear.
    • Frequency: The number of oscillations per second, expressed in hertz (Hz).
    • Amplitude: The maximum extent of a vibration, which determines the loudness of a sound.
    • Noise Pollution: Excessive or unwanted sounds in the environment that may cause health issues.