Waves & how they move · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Amplitude and wavelength: measuring a wave

Science · Waves, Light & Sound · ages 9-10
Name ______________________   Date ____________

  1. One spring has a single isolated bump. Another has a repeating row of neighbouring peaks. Which lets you measure a wavelength from peak to next peak?

    • Only the isolated bump
    • Only the repeating pattern
    • Both patterns in the same way
    • Neither of these patterns

  2. What does the amplitude of an up-and-down rope wave measure?

    • Movement from rest to a peak
    • Distance between neighbouring peaks
    • Distance travelled in one second

  3. For otherwise comparable waves on the same rope at the same shaking rate and tension, a larger amplitude carries more energy.

    Circle one:   True   False

  4. Kai measures straight along a repeating rope wave from one peak to the next peak. Which measurement is he finding?

    • The wave's amplitude
    • The wave's wavelength
    • The wave's travel speed

  5. Mia wants to compare how amplitude affects energy on a rope. Which plan changes amplitude while keeping the other conditions the same?

    • Change the rope and its tension together
    • Change the shaking rate and the rope together
    • Change the tension and shaking rate together
    • Change hand movement but keep rope, tension and rate

  6. Use the simplified water-wave model with no current or drift. A floating cork follows the surface as large-amplitude waves pass. What mainly happens?

    • It bobs up and down
    • It stays at one height
    • It travels with each peak

  7. These bars measure amplitudes of otherwise comparable waves on the same rope at the same shaking rate and tension. Which carries more energy?

    Wave A: 3cm3Wave B: 7cm7
    • Wave A
    • Wave B
    • Equal energy

  8. Knowing only the amplitudes tells you which waves carry more energy, whatever their materials and setups.

    Circle one:   True   False

  9. Wave X has neighbouring peaks 2 cm apart. Wave Y has neighbouring peaks 5 cm apart. Which has the longer wavelength?

    • Wave X
    • Wave Y
    • Equal wavelengths

  10. Three consecutive peaks of a repeating wave are at 1 cm, 7 cm and 13 cm along a ruler. What is one wavelength in cm?

    Answer: ______________

LightMySky · lightmysky.comW1-mt_ph4xZVMiVq-s1

Answer key

For grown-ups. Fold this page away before handing over the rest.

Amplitude and wavelength: measuring a wave W1-mt_ph4xZVMiVq-s1

  1. Only the repeating pattern · The repeating pattern supplies neighbouring peaks. One isolated bump does not.
  2. Movement from rest to a peak · Amplitude is the greatest movement from the resting position, measured from rest to a peak in this wave.
  3. True · The rope, shaking rate and tension match. Under these comparison conditions, larger amplitude means more energy.
  4. The wave's wavelength · The distance along the wave between neighbouring peaks is one wavelength.
  5. Change hand movement but keep rope, tension and rate · Changing only how far the hand moves changes amplitude while the rope, tension and shaking rate stay the same.
  6. It bobs up and down · In the stated model, the cork follows the rising and falling surface. The wave pattern travels past it.
  7. Wave B · Wave B has the larger measured amplitude. With the other conditions unchanged, it carries more energy.
  8. False · Comparing energy using amplitude needs the other conditions to stay the same. Amplitude alone cannot tell you which waves carry more energy when their setups differ.
  9. Wave Y · Compare the peak spacings. Five centimetres is greater than two centimetres, so Wave Y has the longer wavelength.
  10. 6 · The first-to-third distance is 13 − 1 = 12 cm and spans two wavelengths. One wavelength is 12 ÷ 2 = 6 cm.
Worksheet · LightMySky