Coursework for physics - resistance of a wire

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Investigation

Resistance of a wire

Introduction:

In this investigation we will aim to find how the resistance in a wire affects the resistance in a circuit, by firstly changing the type of wire we use and then, in the main test to see how the length of the wire changes the resistance in an electrical circuit. In the pre-test the variable is the type of wire which we used, we used this information to see what wire to use in our main test. In the main we changed the length of a wire to see how the length of the wire will change the resistance in the current.

Hypothesis:

In our investigation we will see how changing the type of wire and the length of wire this affects the resistance for electrons flowing through the circuit. As electrons enter the wire they collide with ions which are a form of resistance. As these electrons move along, and the particles collide, other electrons leave the wire at the other end, as the electrons are pushed out. When you change the type of wire you are changing how the electrons will flow in the circuit, as the different lengths and types of wires have different atoms and spaces between the atoms, the structure changes as well, meaning that the will be a different amount of time that it takes for the current to flow. It takes a short time for these electrons to collide all the way along the wire. If you add more wire, it will take longer for the current to flow through the wire. This is because there are more ions in the wire resulting in it being harder for the current to flow through an extended wire.

Pre-test

Equipment:

  • Battery pack-This will be used to supply power for the experiment/circuit
  • Leads-These connect up the components in the circuit
  • Constantan wire-this is our independent variable
  • Copper wire- this is our independent variable
  • Nichrome wire- this is our independent variable
  • Volt meter-This measures the volts in the circuit
  • Ammeter-This measures the amps in the circuit
  • Meter ruler-Used to measure length of wire used
  • Scissors-used to cut the specific length of a wire.
  • Crocodile clips-to attach the independent variable to the circuit
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Method:

  1. Collect equipment
  2. Measure out 50cm of each wire
  3. Attach the circuit together as it is showing the diagram above
  4. Attach the wire to the circuit
  5. Measure the voltage and amps that are present when using different wires
  6. Repeat experiment at different voltages and using the different wires.

Results for pre-test:

Conclusion for pre-test

From our results we can see that the Constantine is the best wire that we tested as it gave us a slightly smaller range of results, which can be improved by simply changing the ...

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