# Investigating how the Length of a Pendulum Relates to the Time it takes to Swing

Extracts from this document...

Introduction

Table of Contents

INTRODUCTION

SCIENTIFIC KNOWLEDGE

Ruler and guitar string

Interchange between K.E and P.E

Length of arc

Measuring lengths of arcs.

INVESTIGATION

Planing

Prediction

Pretest

Fair test conditions.

Method

Apparatus

Procedure

Analysis

Results

Graph

Conclusion

THEORETICAL EQUATION

EVALUATION

Investigating how the Length of a Pendulum Relates to the Time it takes to Swing

## Introduction

The time of oscillation for a pendulum depends on many factors. I am investigating into these limiting factors and will try and determine how one of these factors effects the pendulum oscillations.

## Scientific Knowledge

## Ruler and guitar string

The vibration of a pendulum can be compared to the vibrations of a ruler or guitar string.

These can be compared because each one obsoletes when it is plucked, pulled or swung. By making it swing different length arches, the pendulum’s pitch can be changed. By having more or less of the ruler on the desk, its pitch can be changed. The position of your finger can affect the pitch of a guitar string a.k.a. the string’s length. All are affected by length and the number of oscillations depends on its length. I will try to discover this ratio with a pendulum.

## Interchange between K.E and P.E

Higher the pendulum the more kinetic energy it has.

## Length of arc

The shorter the pendulum, the less time it takes to swing.

## Measuring lengths of arcs.

30 cm = radius 60 cm = radius

Middle

### Pretest

I carried out a pretest on the pendulum. I took a pendulum at 10 cm. The time was less than a second, I preferred times more than one second long so next I tested 20 cm. Again the time was less than a second, so I tested 30 cm. 30 cm had a time just over a second so I decided to start there. All times are from taking the time for ten swings and dividing.

30 cm | 31 cm | 32 cm | 33 cm | 34 cm | 35 cm |

1.1 s | 1.1 s | 1.1 s | 1.1 s | 1.1 s | 1.2 s |

36 cm | 37 cm | 38 cm | 39 cm | 40 cm | 41 cm |

1.2 s | 1.2 s | 1.2 s | 1.2 s | 1.3 s | 1.3 s |

42 cm | 43 cm | 44 cm | 45 cm | 46 cm | 47 cm |

1.3 s | 1.3 s | 1.3 s | 1.4 s | 1.4 s | 1.4 s |

48 cm | 49 cm | 50 cm | 51 cm | 52 cm | 53 cm |

1.4 s | 1.4 s | 1.5 s | 1.5 s | 1.5 s | 1.5 s |

54 cm | 55 cm | 56 cm | 57 cm | 58 cm | 59 cm |

1.5 s | 1.5 s | 1.5 s | 1.5 s | 1.5 s | 1.5 s |

60 cm | 61 cm | 62 cm | 63 cm | 64 cm | 65 cm |

1.6 s | 1.6 s | 1.6 s | 1.6 s | 1.6 s | 1.6 s |

66 cm | 67 cm | 68 cm | 69 cm | 70 cm | 71 cm |

1.6 s | 1.6 s | 1.6 s | 1.6 s | 1.7 s | 1.7 s |

72 cm | 73 cm | 74 cm | 75 cm | 76 cm | 77 cm |

1.7 s | 1.7 s | 1.7 s | 1.7 s | 1.7 s | 1.7 s |

78 cm | 79 cm | 80 cm | 81 cm | 82 cm | 83 cm |

1.7 s | 1.7 s | 1.8 s | 1.8 s | 1.8 s | 1.8 s |

84 cm | 85 cm | 86 cm | 87 cm | 88 cm | 89 cm |

1.8 s | 1.8 s | 1.8 s | 1.8 s | 1.8 s | 1.8 s |

90 cm |

1.9 s |

From looking at these results I decided that I would have nine lengths.

30, 35, 40, 45, 50, 60, 70, 80 and 90 cm.

I have decided to use these lengths because these are the only lengths that give different times.

Conclusion

I found this experiment quite interesting. It has made me interested in the factors that affect the time of an oscillation of a pendulum. If I were to do further work, I would like to investigate how the starting angle from which the pendulum is dropped affects the time of an oscillation.

This student written piece of work is one of many that can be found in our GCSE Forces and Motion section.

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