Pendulums have been around for hundreds of years, Galileo Galilei was often found swinging, studying and reporting about pendulums all the way back to 1602. Throughout the centuries it has influenced some great scientific minds like Leonardo Da Vinci and Isaac Newton.
 
Pendulums have been used in divination practice by tapping into ones intuition. By acting as a receiver and transmitter it will move in different ways in response to the question. You can ask your pendulum yes and no questions which is the most straightforward way of using this tool of divination.