To experience the important characteristic of wave equations, one can throw a rock in a calm pond and watch propagation of the waves in water. It is important to notice that the disturbance made (by throwing the rock), will reach different part of the pool at different time.

Make a pendulum by attaching one end of a string to wall firmly and take the other end at one’s hand. Now stretch the string first and then make a disturbance in it by moving the end up and down very quickly. One can make a deflection and observe how the impulse travels in the string and how it will come back to you. One should repeat the experiment with a heavier string and with the same string but with more stretching to observe the difference in the speed at which the disturbance moves.