Pendulums- how can a period of a pendulum be increased?
Galileo used pendulums extensively in his experiments. He used pendulum as a timing device and later it was used in clocks. You can still purchase decorative clocks with pendulums. The physics of a pendulum is used almost in any device that has a swinging part. 
 Project description
Pendulum related experiments are safe and can be performed at home with minimum requirements. In this project you will design an experiment in order to find out how you can decrease or increase the period of a pendulum.
 Details of this project