| Sound cannot travel through a vacuum. |
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The alarm clock cannot be heard
because sound cannot travel through a vacuum. |
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Before the air is sucked out of
the bell jar, the clock can be heard ringing. |
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The vacuum pump sucks out the air
and even though the hammer can be seen striking the bell, the
ringing cannot be heard, because there is no air to carry the
vibrations. |
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| Sound travels through all sorts of
materials. It travels very well in solids. |
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A distant train can be heard more
easily if you are near the track because the metal track is a
good conductor of sound. You notice this on a station platform. |
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NEVER
GO TOO NEAR RAILWAY TRACKS!! |
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