Effects of Swing Length, String Length, and Weight on a Pendulum Swing

Abstract

A pendulum was constructed and altered with differing weights, swing lengths, and pendulum lengths. The period for each variation was recorded and compared to find the factors that affected the length of the period. It was concluded that the length of the pendulum was the determining factor for the period of the swing.

Introduction

In 1581, Galileo began studying at the University of Pisa, where his father hoped he would study medicine. While at the University of Pisa, Galileo began his study of the pendulum while, according to legend, he watched a suspended lamp swing back and forth in the cathedral of Pisa. However it was not until 1602 that Galileo made his most notable discovery about the pendulum- the period (the time in which a pendulum swings back and forth) does not depend on the arc of the swing (the isochronism). Eventually, this discovery would lead to Galileo's further study of time intervals and the development of his idea for a pendulum clock. It is important to know the relationship between a pendulum and other parameters, because they can allow you to track the accuracy of time and temperature. We are involved in this experiment because our professor has presented us with the challenge of constructing a pendulum, devising an experiment, and collecting data to support our hypothesis. From this experiment, we hope to learn more about the history of the pendulum and what it is used for today.

Equipment and Method

The pendulum was constructed with a weight (size varies) at the end of a string (length varies) which was attached to a metal base. A meter stick was used for measuring lengths and a stopwatch was used to measure time. We determined the length of the pendulum to be from the point where the string was attached to the base to the end of the (1000 g) weight. Length of the swing was approximated as one meter for a long swing and fifty centimeters for a short swing. One period was determined to be from when the pendulum was released from rest until it returned to it's original position. This was repeated three times for each alteration of variables and averaged to determine the average period of a swing for that set of variables. The 1000 gram weight was used first