Investigate the resistance of a wire at different stages on the power supply.

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Planning

This is the part of my coursework where I am going to plan an experiment that I am to analyse for my work. What we are going to do is to investigate the affects or the variables have on different lengths of constantan wire. I am going to use different lengths which will provide me with a range of results. The reason I want a range of results is so that I can compare and analyse results, which will let me evaluate the readings clearly. First I will tell you a little about how I started. We were set into groups with other pupils, and then together we set out and did our preliminary experiment. The preliminary experiment is very important, because it is like a practice for the real thing. Also it helps as here you can make mistakes, so when doing the real experiment errors can be eliminated. I will explain how we did the preliminary experiment and include all the steps we took.

For my introduction I want to start off by just explaining a little about the material that we are using, as this is vital so we know what is harmful and what is not, which can help with safety.

The power supply – we will be using one of these. This can be dangerous if not used safely. We should know that the power supply should not b left on for more than a few seconds, with certain wires, as it can blow the system. When plugging the plug in, you must make sure the switch is off. This may sound obvious, but is a safety regulation. Also you should never plug the plug in to the socket if your hands are wet, as you may end up experiencing an electric shock.

Wires – the constantan wires we are using are not dangerous, but they are quite sharp on the ends, so they should be handled with care, and never be raised off the table.

This is the main apparatus we are using, and knowing what I have said is a safety feature. If we follow this we would end up having a safe experiment.

I will go on now to explain about my preliminary experiment. We did this in the same groups as we were to do in the main experiment, which helps with remembering what we did in the experiment. My prelimnary experiment was quite simple, but still procedures had to be followed.

My procedure

Title – Investigate the resistance of a wire at different stages on the power supply.

In order to start the experiment we needed to get all the apparatus out. Before that we cleared are tables and made the area a clean working environment. Then we got all the apparatus we needed to set up the experiment. For the experiment the apparatus included –

  •  Volt meter
  • Ammeter
  • Crocodile clips * 2
  • Pliers
  • Metre ruler
  • Connecting wires
  • Power supply
  • Constantan wire ( specific one, mentioned below)

The constantan wire is the same length throughout the experiment that I did. The measurement that I used was 26 SWG. 0.45 mm in thickness.

With this I did my experiment.

Method

Firstly I got all my equipment out, and neatly placed it out making sure it wasn’t in anyone’s way. Then I started to connect my experiment. When connecting wires, I made sure that the ammeter was placed in series and the voltmeter was in parallel. I set it up like the diagram shows below.

Then once I had the apparatus ready, I placed my wire in between the clips, and then started the power supply. When I switched on the power supply, the ammeter and voltmeter gave readings, which we quickly took down. Then we increased the power supply from 2 volts up to 10 volts. Then we did this same method for all the tests. After we had noticed that there was a pattern in the results which are listed below.

Conclusion

From my set of results, I can see that the test went well, so I can’t identify any anomalies due to the fact that we did not make mistakes. The results were pretty much as we expected.

 

Then I move on to my experiment which I will do. This is no longer the prelimnary work, so I have to be as careful as I can be so that my experiment goes well and just the way I want it to go.

For my main experiment what I plan to do is to simply get a lot more results using different methods. We as a group have decided to use two different variables; this will provide a greater range of results. I feel that it is important to carry out my experiment carefully in order to achieve a good set of results.

My aim for the experiment which I am going to do is to investigate the affects or the variables have on different levels of constantan wire. What I have decided to do is to use different levels of wire, which will help again in range. My plan is to do more tests, but I am going to change the tests by changing the lengths of the wires each time. What I mean is I am going to cut the wires, then test them, this time the wires will vary in width. I have decided to start with a wire which is 1 metre long, then 90cm, then 80cm and so on, all the way to 10cm. I will do this for different wires, which will have a different SWG number. I will set up the experiment the same way as the preliminary and then do my tests, using the same experiment.

Throughout my experiment, I as well as my group want to do everything in a safe and clean manner. The only way to do this is to take safety precautions and know how they are dangerous. For safety reasons, we will clear are tables from any sort of books and stationary. We could use safety goggles, but there are no harmful products as we are not using liquids, which mean there is minimal chance of anything hurting the eye. We will be weary of other pupils, and not get in the way. Also bags will be neatly tucked under the table, so if we were to move we wouldn’t fall. Running in the room is strictly forbidden, it is dangerous to run as you can hurt yourself. One of the most basic rules we should never forget is the fact that we are working in a lab, so no eating and no drinking is aloud. People do forget how easy it is to pass on bacteria from one person to the other, and the easiest way for bacteria getting in is through the mouth. Throughout my experiment, my group will not forget to play along side with the classroom rules, and the lab rules. The pliers should, like anything we touch, be handled with extreme care, and when holding the pliers, we will keep the pliers low down. I believe that if we follow all these rules, then there will be no mistakes, and we will end up with good results. All talking will be done quietly and only amongst are group. Another safety measure that people forget is that if you break something in class, it should be immediately told to the teacher for safety.

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The apparatus that I am going to use in my main experiment are as follows

  • Volt meter
  • Ammeter
  • Crocodile clips * 2
  • Pliers
  • Metre ruler
  • Connecting wires
  • Power supply
  • Constantan wire

These apparatus will be handled with care, as it is important that I set it all up correctly and safely.

I want my results to be extremely good, and just the way I predicted them to be. The information and the results that I am using is first hand experience. I am going to do each experiment and ...

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