# A technician has the problem of making wire resistors of various values. Plan and carry out an investigation to help the technician solve the problem.

Statement of the problem.

A technician has the problem of making wire resistors of various values. Plan and carry out an investigation to help the technician solve the problem.

## Background

Resistance is the property of a material, which opposes the current through the material. The larger the resistance the smaller the current flowing through the circuit. Resistance is measured in ohms (Ω). To find resistance we use the formula: resistance = voltage / current  (R=V/I)

To find the current we must use an ammeter and to find voltage we must use a voltmeter.

In series circuits the total resistance is just the sum of all the resistance’s. In a parallel circuit the current through each component depends on its resistance. The lower the resistance the bigger the current that’ll flows through it.

## Variables

There are four variables:

1. length
2. temperature
3. material
4. cross section area of wire

I am going to test number one, the length of wire.

## Predictions

I predict that has I increase the length of wire, the resistance will also increase. The length of a wire affects its resistance to the flow of the charges through the wire. This determines how much current (i.e. flow of charge i.e. electrons) flows in the wire.

## Independent

This is the length of wire we will use in the circuit in which the current will flow and the voltage.

## Dependant

This is what we measure; this will be the current and resistance.

Control

This is what is kept the same. This will be the other variables: temperature,

cross section area of wire and material.

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