Sound - Cracking the Sonic Code - Physics Chapter 7, ICSE Class 8 скачать в хорошем качестве

Sound - Cracking the Sonic Code - Physics Chapter 7, ICSE Class 8

Sound is a form of energy that creates the sensation of hearing and is produced when an object vibrates. In air, sound travels as a longitudinal wave, which consists of regions of high pressure called compressions and low pressure called rarefactions. During this process, the particles of the medium vibrate back and forth about their mean positions to transfer energy but do not actually move from the source to the listener. The "strength" and "speed" of these vibrations are measured by amplitude and frequency. Loudness depends on the amplitude of the vibration; for example, striking a drum harder increases the amplitude, making the sound louder. This loudness is measured in decibels (dB), with the safe hearing limit being between 0 to 80 dB. If a sound exceeds 120 dB, it is considered painful noise that can cause permanent ear damage. Other key characteristics include pitch and quality. Pitch is the shrillness of a sound and depends on its frequency; higher frequency results in a higher, shriller pitch, like a crying baby or a flute. Musical instruments change pitch by adjusting things like string tension or the length of an air column. Finally, quality (or timbre) is the characteristic that allows us to distinguish between two different instruments, like a piano and a violin, even when they play the same note at the same loudness, because they have different wave forms. Analogy for Sound Waves: Think of a "human wave" in a sports stadium. The people (the particles) just stand up and sit down in their own spots (vibrate), but the wave itself (the energy) travels all the way around the stadium. Similarly, sound energy moves through the air while the air particles stay in their general area. Other chapters from ICSE Class 8 Physics book: Ch. 1 Matter    • Matter, The Science of Matter - Physics Ch...   Ch. 2 Physical Quantities and Measurements    • Physical Quantities and Measurement, The S...   Ch. 3 Force and Pressure    • Force and Pressure - Physics Chapter 3, IC...   Ch. 4 Energy    • Energy, Work and Power - Physics Chapter 4...   Ch. 5 Light Energy    • Light Energy, Light Bending & Bouncing - P...   Ch. 6 Heat Transfer    • Heat Transfer, The Hidden Power of Heat - ...   Ch. 7 Sound : this chapter Ch. 8 Electricity    • Electricity - The Power in Your Wall - Phy...   #dohrao #dohraoicseclassh8 #icseclass8 #icse #icseclass8 #dohraoicseclass8