To demonstrate a standing wave using a string, one effective method involves fixing one end of a long, thin rope or string to a stable surface and creating tension. Light strings may be challenging due to low mass and air dampening effects, making it harder for reflected waves to sustain themselves. A simple setup can include a small electric motor, a pulley, and weights to replicate Melde's experiment. Alternatively, using sewing elastic with popsicle sticks glued along the string can visually enhance the demonstration. This approach allows for an engaging observation of standing waves in action.