This is a lab exercise where students make observations of slinkies (I recommend metal ones) to determine the structure and motion of mechanical waves. The activity is recommended to be done with 2 students per slinky, but no more than 3 as it takes away from the learning experience.
The ultimate goal is for students to notice the difference between how a Longitudinal or Compression (parallel wave motion to disturbance) wave moves and a Transverse wave's motion (perpendicular wave motion to disturbance). The observation portion of the lab with the slinky has follow-up analysis questions that get students to process and breakdown what they observed about the slinky's behavior when providing a disturbance in one end of it.
Some management will be required when using the slinkies as they get bent and tangled easily! Be sure to set standards of conduct with lab equipment prior to starting the lab.