Test yourself

Boss quiz

10 questions on the whole topic. You get one try at each.

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  1. What does a wave carry from place to place?

    • Energy
    • Air
    • Water
    • Particles

  2. What does every sound start with?

    • A flash of light
    • A vibration
    • Still air
    • A vacuum

  3. How do the particles of the air move when a sound wave passes?

    • Back and forth, along the line the wave travels
    • Up and down, across the line the wave travels
    • They do not move at all
    • Along with the wave, all the way to your ear

  4. Why can sound not travel through a vacuum?

    • A vacuum reflects all sound
    • There are no particles to pass the vibration on
    • A vacuum is too cold
    • Sound is too slow to cross it

  5. Through which of these does sound travel fastest?

    • Water
    • Steel
    • A vacuum
    • Air

  6. A guitar string is plucked harder. On an oscilloscope its wave gets taller. What has changed?

    • The frequency is higher, so the sound is louder
    • The amplitude is bigger, so the sound is louder
    • The amplitude is bigger, so the pitch is higher
    • The frequency is lower, so the sound is quieter

  7. One sound has a frequency of 100 Hz. Another has a frequency of 1000 Hz. How does the second one sound?

    • Lower in pitch
    • Louder
    • Quieter
    • Higher in pitch

  8. What is an echo?

    • A sound reflected from a surface
    • A sound absorbed by a surface
    • A sound made in a vacuum
    • A sound too high to hear

  9. A dog whistle makes a sound of 30 000 Hz. Why can a dog hear it when you cannot?

    • It is above your hearing range, but inside the dog’s
    • It travels faster to a dog
    • It is too quiet for human ears
    • A dog has bigger ear drums

  10. What is ultrasound?

    • Sound with a frequency too high for humans to hear
    • Sound that is too loud for humans to bear
    • Sound with a frequency too low for humans to hear
    • Sound that travels faster than other sound
Answers
  1. Energy. A wave carries energy. The water, rope or air it travels through is left behind.
  2. A vibration. Something has to vibrate, such as a drum skin.
  3. Back and forth, along the line the wave travels. Sound is a longitudinal wave. Each particle moves back and forth about one place.
  4. There are no particles to pass the vibration on. Sound is passed on from particle to particle. A vacuum has none.
  5. Steel. Sound is fastest in solids, where the particles are closest together. It cannot cross a vacuum at all.
  6. The amplitude is bigger, so the sound is louder. A taller wave has a bigger amplitude. A bigger amplitude means a louder sound.
  7. Higher in pitch. A higher frequency means a higher pitch.
  8. A sound reflected from a surface. An echo is a reflection of sound. Hard surfaces such as cliffs reflect sound well.
  9. It is above your hearing range, but inside the dog’s. You can hear up to about 20 000 Hz. A dog can hear up to about 45 000 Hz.
  10. Sound with a frequency too high for humans to hear. Ultrasound is above 20 000 Hz, the top of the human hearing range.