Final answer:
Mechanical waves cause particles to move up and down when they travel through a medium.
Step-by-step explanation:
From the activity described, it can be concluded that mechanical waves cause particles to move up and down when the wave travels through a medium. This is evident in the example of a cork dropped into a pool of water, where waves are created and propagate outward from the cork. The particles of the water move up and down as the waves pass by, while the cork remains in its original position. This motion of the particles is characteristic of mechanical waves.