Resistance in a Nichrome Wire.

1. The type of wire
2. The thickness of the wire

Safety Precautions,

There are not many safety precautions that need to be taken in this experiment but there are still a few.

Do not carry out the experiment in wet areas as water is a very good conductor of electricity and this could be dangerous.

Do not touch the wire when the multi meter is on, because the current will heat up the wire so it will be very hot.

Place a wire in a cool beaker of water to keep the temperature of the wire down so that it will not burn away.

Also do not fool around when the experiment is under way as this could cause in glass smashing or something else.

Apparatus

Multi-meter,

Amp-meter,

100cm of Nichrome wire,

Meter Ruler,

Crocodile clips,

Sellotape,

Connection leads,

Beaker of water,

Wire Cutters,

And pen and paper to record my results.

I set up the experiment as shown above.

I started the experiment by sellotaping one end of the Nichrome wire (over 100cm long) to the meter ruler. I then cut it off with the wire cutters. After that we coiled the wire as tight as possible around the pencil and connected either end to a crocodile clip. We then added the am-meter parallel with the wire. The wire was put into the beaker full of cool water with the crocodile clips taped to the edge of the beaker. The clips shouldn’t touch the water as the electric current might flow through the water causing it to give of a false reading. Then the multi-meter was switched on. The resistance was then recorded down for various lengths, ranging from 0 50v, 100cm. I then plotted theses results on a graph.

        To collect the data for my graph I had chosen to take a range of ten lengths. I had chosen a range of ten results to plot a more accurate graph I will need at least ten points to mark on the graph. The lengths that I had chosen were 10cm, 20cm, 30cm, 40,cm 50cm, 60cm, 70cm, 80cm, 90cm, and 100cm. I chose these lengths because they are easily measured on a ruler and give a good range of results.

Evaluation:

I think that overall my experiment was quite accurate and very good. All though I think that it might have been slightly inaccurate, because my measurements of wire may not have been too accurate, it is too hard, to get an exact reading by eye. This might have been a slight fault but I don’t think it was that bad. So I don’t think that this factor affected my results too much. To have made the experiment possibly more accurate I could have recorded the results three times and found the average but I did not have enough time to of done that.

        I found it very easy to set up the experiment, as it was quite simple. I didn’t come across anything to hard during the experiment apart from getting the exact current by turning the knobs. This became a bit tricky. I never needed any help from my teacher either.

        I found that my prediction was quite accurate as when the wire was longer it was harder for the current to flow through which was the resistance. In my experiment I followed all of the safety rules correctly and my work area was kept tidy at all times.

By Paul Cosgrove 11C