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NON-TRANSMISSION OF SOUND IN A VACUUM








EQUIPMENT
    redball.gif (326 bytes) Bell Jar
    redball.gif (326 bytes) Buzzer
    redball.gif (326 bytes) Vacuum Pump
   


NARRATIVE
            Sound must have a medium in which to travel. Connect the buzzer terminals to a 6 Volt DC battery. Switch the buzzer on. Connect the hose from the vacuum pump to the outlet of the Bell Jar. Begin pumping air from the jar. As the jar becomes evacuated, the buzzer continues to vibrates but the sound cannot be heard. Slowly vent air back into the jar and the buzzer becomes audible again.