Medium — Science definition

Defined in 2 courses:

Where it is taught

In use

Ordinary sound needs a material medium such as air, water, or a solid.

Sound Waves

Because sound is nothing more than particles jostling their neighbors, it absolutely requires a medium — which is why space is silent, and why the booming explosions in science-fiction films could never actually reach your ears across a vacuum.

Sound

Questions using medium

Problem 1

An illustrative echo returns 0.30 s after a short sound. The modeled sound speed is 340 m/s, and the path goes from source to wall and back. Find one-way distance and explain the medium’s role. Distinguish particle motion from the travelling disturbance.
Answer and explanation

The round-trip path is 340×0.30=102 m, so one-way distance is 51 m. Ordinary sound needs matter, with successive compressions and expansions transmitting a disturbance. Individual air particles mainly oscillate near their positions rather than travel the complete path. The arithmetic assumes the stated speed and clear timing.

The round-trip path is 340×0.30=102 m, so one-way distance is 51 m. Ordinary sound needs matter, with successive compressions and expansions transmitting a disturbance. Individual air particles mainly oscillate near their positions rather than travel the complete path. The arithmetic assumes the stated speed and clear timing.

Response criteria

  • Use the supplied conditions and relevant evidence.
  • Explain the scientific mechanism or calculation.
  • State a meaningful limitation or testable next step.

Problem 2

Explain the following claim and supply a valid example or counterexample: Sound requires a medium; pitch and loudness measure different aspects.
Answer and explanation

Round-trip 170 m; one-way distance 85 m. Sound requires a medium; pitch and loudness measure different aspects.

Response criteria

  • State a scientifically accurate conclusion.
  • Show the calculation or mechanism that supports it.
  • Include units, conditions, or limits where relevant.

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