<\/p>\n
Sound plays an important role in our daily life. It helps us to communicate with one another and express yourself.<\/p>\n
Sound is produced by vibrating the objects and it is carried in all directions with the help of a medium.<\/p>\n
Sound needs a medium to travel. It cannot travel in a vacuum.<\/p>\n
We hear sound through our ears.<\/p>\n
The eardrums of our ears sense the vibrations produced by a vibrating object and send them to the brain as the stimulus. This process is called a hearing.<\/p>\n
Frequency:<\/strong> The number of oscillations or vibrations per second is called the frequency of oscillation.<\/p>\n Noise Pollution:<\/strong> The presence of excessive or unwanted sound in the atmosphere is called noise pollution.<\/p>\n Major causes of noise pollution are sounds of vehicles, explosions including the bursting of crackers, machines, loudspeakers etc.<\/p>\n Presence of excessive noise in the surroundings may cause many health-related problems e.g., lack of sleep, hypertension and anxiety etc.<\/p>\n Plantation on the roadside and elsewhere is the best source to reduce the noise pollution.<\/p>\n The loudness is expressed in a unit called decibel (dB). It also depends on the amplitude of the sound.<\/p>\n Amplitude:<\/strong> The maximum distance to which a vibrating body moves on either side of its mean position is called the amplitude of vibration.<\/p>\n Audible Frequencies:<\/strong> For human ears, the range of audible frequencies is roughly from 20 to 20,000 Hz.<\/p>\n Eardrum:<\/strong> A thin membrane which is stretched tightly to receive the waves bf sound at the end of ear canal.<\/p>\n Hertz:<\/strong> The frequency is expressed in hertz (Hz).<\/p>\n Larynx:<\/strong> In humans, the sound is produced by the larynx.<\/p>\n The loudness of Sound:<\/strong> Larger the amplitude of vibration, louder is the sound.<\/p>\n Noise:<\/strong> Unpleasant sounds are called noise.<\/p>\n Oscillation motion:<\/strong> The to and fro motion of an object is called oscillation motion.<\/p>\n Pitch of the Sound:<\/strong> Higher the frequency of vibration, the higher is the pitch, or shrill of the sound.<\/p>\n Shrillness:<\/strong> The frequency determines the shrillness or pitch of a sound. If the frequency of vibration is higher we can say that sound is shrill.<\/p>\n Time Period:<\/strong> The time taken by a pendulum to complete one oscillation is called the time period.<\/p>\n Vibration:<\/strong> The to and fro or back and forth motion of an object is termed as vibration.<\/p>\n Voice Box:<\/strong> Upper end of the windpipe, below the hard part on the throat is called the voice box.<\/p>\n Windpipe:<\/strong> It is the passage for the inlet and outlet of air in the lungs.<\/p>\n We hope the given CBSE Class 8 Science Notes Chapter 13 Sound Pdf free download will help you. If you have any query regarding NCERT Class 8 Science Notes Chapter 13 Sound, drop a comment below and we will get back to you at the earliest.<\/p>\n","protected":false},"excerpt":{"rendered":" CBSE Class 8 Science Notes Chapter 13 Sound Sound plays an important role in our daily life. It helps […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_yoast_wpseo_focuskw":"CBSE Notes science","_yoast_wpseo_title":"","_yoast_wpseo_metadesc":"Get Sound Class 8 Notes Science Chapter 13 on Infinity Learn.","custom_permalink":"study-material\/cbse-notes\/class-8\/science\/sound-class-8-notes-science-chapter-13\/"},"categories":[92,116,21],"tags":[],"table_tags":[],"acf":[],"yoast_head":"\n