Which type of wave moves like a slinky?

The type of wave that moves like a slinky is a longitudinal wave. In a longitudinal wave, the particles of the medium move back and forth in the same direction as the wave. As you compress and release a slinky, you create areas of compression (where the coils are close together) and rarefaction (where the coils are spread apart). This movement mimics the arrangement of particles in a longitudinal wave, where energy is transferred through these compressions and rarefactions along the direction of the wave's propagation.

In contrast, a transverse wave has particles that move perpendicular to the direction of the wave's travel, like the motion of waves on a string where peaks and troughs are created. Surface waves, which occur at the interface between different mediums, combine characteristics of both transverse and longitudinal waves but do not directly resemble the motion of a slinky. Electromagnetic waves consist of oscillating electric and magnetic fields and do not require a medium to travel through, making their behavior fundamentally different from what is seen with a slinky.