# Find out the relationship between resistance and conductive putty, and to see how length of putty affects this relationship.

Extracts from this document...

Introduction

Aim:

The aim of this investigation is to find out the relationship between resistance and conductive putty, and to see how length of putty affects this relationship.

The Experiment:

Conductive putty is specially designed to be a conductor; this is achieved by adding carbon black. This can easily be used to prove the concept of resistivity because it is malleable and so the cross-sectional area, length and shape can easily be changed.

This experiment will show the effects on resistance in a circuit, as the length of putty decreases.

I will be using 30cm of putty, and decreasing it by 5cm each time.

First the voltage of the battery will be taken using a voltmeter, and this will be recorded at the start of the experiment. Then a circuit will be constructed containing the battery, the ammeter and putty. See diagram. For each different length of putty, a reading will be recorded from the ammeter and when the practical has been completed, I will work out the resistance using the formula R=VI. From those results I will draw a graph and then evaluate and conclude my experiment.

Diagram:

Constants:

My constants include the weight of my putty – I am going to start each experiment with 50g of putty.

Middle

## Experiment 1 – battery voltage = 6.12V:

## Length of putty in cm | ## Amps in A | ## Resistance in Ω |

## 30 | 0.06 | 102 |

## 25 | 0.08 | 76.5 |

## 20 | 0.10 | 61.2 |

## 15 | 0.13 | 47.08 |

## 10 | o.14 | 43.71 |

## 5 | 0.25 | 24.48 |

## Experiment 2 – battery voltage = 6.03V:

## Length of putty in cm | ## Amps in A | ## Resistance in Ω |

## 30 | 0.05 | 120.6 |

## 25 | 0.06 | 100.5 |

## 20 | 0.08 | 75.37 |

## 15 | 0.11 | 54.81 |

## 10 | 0.15 | 40.2 |

## 5 | 0.27 | 22.33 |

Conclusion

## If this experiment was going to be redone, then I think I might use a new battery for each experiment, and record the voltage as constant for all experiments. Also I would maybe use a different method to connect the wires to the putty, like maybe sticking the wires directly and vertically into the ends of the putty. Another thing to do would be to use temperature or even cross-sectional area as a variable alongside length, and to do a series of experiments involving increasing the length while decreasing the cross-sectional area, and vice versa.

## Conclusion:

## I think this experiment was a success in that it proved the theory that resistance is lower with shorter lengths of conductor and my hypothesis declares that as the electrons have a shorter distance to travel if the length is shorter, there are fewer collisions and less energy is lost to heat unlike in a longer length of conductor, so the putty will have lower resistance. Therefore my hypothesis was correct and I have successfully concluded my experiment proving that resistance is directly proportional to the length of conductor.

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

## Found what you're looking for?

- Start learning 29% faster today
- 150,000+ documents available
- Just £6.99 a month