Alberta Grade 8 Science Light and Optical Systems Practice Test 2026 – Complete Study Resource

Mechanical waves require a material medium to carry the energy, moving by vibrating the particles of that medium. Ocean waves ride on water, seismic waves travel through rocks, sound waves move through air (or other substances), and a slinky demonstrates a wave traveling along a solid medium. The other options are all electromagnetic waves, which can travel through empty space without a medium—light (including infrared and ultraviolet), radio waves, and X-rays. Since mechanical waves need a medium to propagate, the first set of examples best fits.