An Investigation into a Factor That Affects the Resistance of a Piece of Wire

Skill P

Planning

Introduction

The resistance of a piece of wire is the determined by the speed that an electrical current can pass through it. Every object that conducts electricity has resistance as no object have no resistance, although some do have very low resistances. This is due to the fact that many different factors affect the resistance.

Key Factors

The possible factors I can investigate are:-

Diameter
Length
Temperature
Material

I shall Investigate Diameter, as it is the easiest to get accurate results with.

Research

Resistance involves collisions of the current-carrying charged particles with fixed particles that make up the structure of the conductors. A current is the amount of charge that goes through any particular part of the wire at any particular time, which is caused by the movement of electrons, although it is usually measured in coulombs, which is ‘electrons per second’. A resistor is a material that makes it hard for electrons to go through a circuit. Without resistance, the amount from even one volt would be infinite. Resistance occurs when electrons travelling along the wire collide with the atoms of the wire.

Hypothesis

I predict that as the diameter increases, the resistance will decrease. This hypothesis is mostly based on preliminary work that I did (see ‘Preliminary Work’) and Ohms Law, Which states that the current is directly proportional to the voltage. Therefore the Resistance will be inversely proportional to the Current as:-

Resistance= Voltage

Current

Therefore as the current increases the resistance decreases and so they must be inversely proportional. I predict that the graph of Resistance against 1/Amperes will be a straight line going through the axis as the Resistance and Amperes will be inversely proportional:- ...