When you put together and hang the finished model on your wall, start it up by pulling the driving weight down. The open mechanism will start moving, the gears will start spinning and all the intricacies will come to life! The pendulum will begin to sway steadily in a steady rhythm. You will relax so that you can concentrate your thoughts on more pleasant events and people. Attach coins to the weight or along the inside of the pendulum. The number of coins affects the period of the pendulum. Because of friction and changes to the center of gravity, the heavier the "sinker", the longer it takes for the pendulum to swing.