Sound Full Chapter Class 8 Science | NCERT Science Class 8 Chapter 13

Magnet Brains・2 minutes read

Sound is produced through vibrations, with vocal cords responsible for human sound production. The process of sound reaching the ear involves vibrations passing through the ear canal to the brain, crucial for communication and understanding.

Insights

  • Understanding how sound is produced through vibrations, such as vocal cords vibrating to create sound, is crucial for communication and hearing processes.
  • The speed of light being faster than sound explains why lightning is seen before thunder is heard, highlighting the difference in speeds between these two phenomena and the resulting delay in sound perception.

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Recent questions

  • How is sound produced in humans?

    Through vocal cords vibrating when air passes.

  • What is the role of vibrations in sound production?

    Vibrations are crucial for creating sound waves.

  • How does sound travel to the ear?

    Sound waves pass through the ear canal to the eardrum.

  • What are some sources of noise pollution?

    Loudspeakers, automobile horns, and phone ringing.

  • How can noise pollution be reduced?

    By using sound-absorbing materials and planting trees.

Related videos

Summary

00:00

Essential Sound Production and Communication Process

  • Sound is essential for communication and is produced by various sources like horns, music, and nature.
  • Humans also produce sound through vocal cords and musical instruments like harmonium.
  • Vibrations are crucial in sound production, as seen when striking a metal plate or a copper cup.
  • Sound is produced through vibrations, as demonstrated by waves in water when a copper vessel is struck.
  • The vibrating body in humans responsible for sound production is the vocal cords.
  • Vocal cords vibrate when air passes through them, producing sound.
  • Sound requires a medium to travel, such as air, water, or metal, as demonstrated by activities involving pipes and water.
  • The process of sound reaching the ear involves vibrations passing through the ear canal to the eardrum and then to the brain.
  • The eardrum vibrates upon receiving sound, transmitting vibrations to the brain for interpretation.
  • Understanding the process of sound production and how it reaches the ear is crucial for communication and hearing.

20:11

"Understanding Sound: Vibrations, Waves, and Pollution"

  • Sound is produced through vibrations, similar to how rubber vibrates when touched.
  • The letter 'A' gets hot when producing sound due to vibrations.
  • Harihar and Green are individuals who send messages by pressing 'Enter.'
  • Shubhendu will discuss the properties of sound next, starting with amplitude.
  • Sound waves are vibrations that travel in the form of sound.
  • The distance between the topmost two points in a wave is called wavelength.
  • Frequency is a property of sound related to the number of vibrations per second.
  • Noise pollution can lead to stress, hypertension, and lack of sleep.
  • To limit noise pollution, rules like avoiding loudspeakers after 11:00 PM have been implemented.
  • Methods to reduce noise pollution include using sound-absorbing materials and planting trees.

40:37

Impact of Noise Pollution on Mental Health

  • Noise pollution can be considered as music in a 10-board colony, impacting mental health negatively, but music itself can be beneficial mentally. Instruments like Sitar, Tabla, and Guitar are essential for music production, reducing noise from automobiles outside.
  • Sources of noise pollution include loudspeakers, automobile horns during traffic jams, continuous phone ringing, and loud sounds from events like marriages or Diwali crackers. Understanding the structure of vocal cords and their vibrations can explain variations in voice quality among individuals.
  • The speed of light being faster than sound results in lightning being seen before the sound of thunder is heard. This phenomenon is due to light traveling faster than sound, with the speed of sound being slower, leading to a delay in hearing the sound after seeing the light.
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