1. You are using an outdated browser. Please upgrade your browser to improve your experience and security.
      Question: The speed of sound is constant.
      Answer: The speed of sound varies because of environmental conditions such as air pressure and humidity.
      Question: It takes a long time for sound to damage human hearing.
      Answer: An extremely loud sound of over 130 decibels can damage hearing right away. Sounds of 85 decibels or more can cause damage if there is exposure over a period of time.
      Question: A microphone works much like a loudspeaker.
      Answer: Many microphones work like audio speakers, transforming sound into an electrical impulse and the reverse.
      Question: No one has reached the speed of sound on land.
      Answer: In 1997 an English driver named Andy Green reached a land speed of 1,228 kilometers per hour, breaking the sound barrier.
      Question: The higher the pitch of a piano note, the lower the frequency of the sound wave.
      Answer: The higher the pitch, the higher the frequency of the sound wave. Sound waves look like ocean waves; some are short and tall, others low and long.
      Question: The way we pronounce words changes as we age.
      Answer: As humans grow old the shape of their mouths and alignment of their teeth changes slightly. This affects pronunciation, making an "s" sound like a whistle, for example.
      hearing. headphone. earphone. iPod. Close-up of human ear with earbud in human head listening to mobile phone or music. Audio equipment communication, ear bud headphones, earbuds, noise sound ear canal.

      Sound: Fact or Fiction?

      ? BananaStock/Thinkstock
      :{{vm.state.secondsLeft|fixedLength:2}}
      {{(vm.state.currentQuestion + 1)}} of {{vm.questions.length}}
      {{vm.state.score|number:0}}
      Sound: Fact or Fiction?
      You finished!
      Your Score: {{vm.state.numberCorrect}} / {{vm.questions.length}}
      Play Next Quiz See All Quizzes
      :{{vm.state.secondsLeft|fixedLength:2}}
      {{(vm.state.currentQuestion + 1)}} of {{vm.questions.length}}
      {{vm.state.score|number:0}}
      {{vm.state.nextLabel}}
      {{vm.state.numberCorrect}}/{{vm.questions.length}} correct
      {{vm.state.score|number:0}}/{{vm.maxPoints}} points
      Replay
      Your results
      Question {{($index + 1)}}
      Your Answer:
      {{vm.state.responses[$index].isCorrect ? 'Your' : ''}} Correct Answer:
      Are you a quizmaster?
      Compare your score
      Max Score: {{vm.maxPoints}}
      {{vm.state.score|number:0}}
      {{vm.communityAverage|number:0}}
      Your Score
      Community Average
      High scores
      or to track your quiz stats, save your best scores, and compete with the community!
      Get kids back-to-school ready with Expedition: Learn!
      Subscribe Today!
      老司机在线视频