Friday, June 20, 2008

Sound by 2E1 Desiree Ang



What is sound?
CRASH BANG! Did you hear that sound? This is called sound and you hear sound everyday. Sound is a form of energy and they are produced by the vibration of objects and the number to count vibration/sec is frequency. Frequency is measured in hertz (Hz).


Transmission of sound.
Sound travels through solid, liquids and gases in 330m/s from one place to another. However, sound cannot travel through a vacuum. Sound travels in a form of waves.

Pitch and music.
A musical note is called a tone which is produced by air vibrating a certain number of times per second. Some instruments have a string, reed or some other devices to create sound waves when moved. A high pitch has high frequency while a low pitch has low frequency. For wind instruments, the shorter the column of air, the higher the pitch of a note.


Natural sound producer.
Our vocal cords are our natural sound producer.


The human ear.
It is a sound detector and it has 3 main parts. The outer ear, middle ear and inner ear. The human ear can only hear a limited range of sound frequencies.


The importance of sound
Sound is a form of communication and warning signal. So it is important. However, noise that is loud, is unpleasant. Sounds above 90dB can cause damage to our ears and if you want to reduce noise level, ear protectors are used. Sound frequencies that are higher than those detected by humans, are used as ultrasound used in the medicinal industry.
A world without sound can cause one to be lonely and lost. Hence, sound is important!


Credits`: http://library.thinkquest.org/5116/sound.htm and science discovery 2 (textbook)

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