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    sound for sixth grade

    شاطر

    esraao

    عدد المساهمات : 18
    تاريخ التسجيل : 18/12/2009
    العمر : 19

    sound for sixth grade

    مُساهمة  esraao في الإثنين فبراير 01, 2010 4:13 am

    sound:
    it is a form of energy that reproduce due to the vibration of an object causing the sensation of hearing.
    - the sound stops when the vibrating body stops its vibration
    - Sound travels through gases (air).
    - Sound travels through liquids (water)
    - Sound travels through solids.



    How does the sound travel through the air?
    - When the body vibrate, the molecules of the air become very close to each other forming compressions.
    - When the molecules of the air become far apart from each other rarefaction is formed, so that sound wave consists of repetition of compressions and rarefactions
    .


    Noise pollution:

    - The sound that causes disturbance and harm to the ears


    Some sources of noise pollution:
    - Loudspeakers.
    - Car horns
    - Machines of workshops and factories



    Effect of noise on Human's health:
    - Exhausting of vocal cords.
    - Hearing weakness.
    - Fatigue of the nervous system

    . .







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    science

    عدد المساهمات : 23
    تاريخ التسجيل : 01/12/2009

    thank you

    مُساهمة  science في الخميس فبراير 11, 2010 6:19 am


      الوقت/التاريخ الآن هو الأربعاء ديسمبر 07, 2016 9:20 am