Safety
I will be careful using main electricity, doing things such as plugging and unplugging the VVPS. I will also be careful not to leave the electro magnet on to long as the wire will start to melt. Finally, I will put something soft underneath the electro magnet. This is encase the weights suddenly come off. This will stop the weights from breaking, and the desk from being damaged.
Number and range of results
I will take 6 sets of results so I can plot an accurate graph. I will repeat my experiment three times and take an average. I will then plot my averages on the graph and analyse my results. I will have eight coils on my magnet, and suspend the magnet 40cm above the ground.
Prediction
The magnet gets stronger as the amplitude (current) increases; the reason for this is the domain theory. This is when in a magnetic material all the atoms are arranged so that each side has an opposite polarity (North and South). In a material, which is not magnetic, these atoms are not arranged, therefore cannot pick up materials such as iron. In an electromagnet the higher the ampage supplied to a circuit, the more atoms are arranged. Though when all the atoms are arranged, the magnet cannot become stronger. This means, as the magnet gets stronger, due to the increase in amplitude (current), it will hold more mass.
Preliminary Experiment
These are my preliminary results with ten coils:
0.1 Amps held 0g
0.5 Amps held 100g
0.6 Amps held 300g
0.8 Amps held 400g
1.0 Amps held 500g
The resistance of the wire is about 0.435 Ohms (1/2.3)
By doing these I have discovered that it is best to have no more than eight coils, if I have less then magnet will be to strong and I will have to use lots of weights, and if I use less it will be to weak and not hold many. Also the voltage is too small to measure, so I will measure the amplitude (current) as it is in whole numbers. I have chosen to use the range 0.0, 0.2, 0.4, 0.6, 0.8, 1.0 this is as is get an even spread of results.
Obtaining Evidence
I made my results as accurate as I could. I did this by using a digital display ammeter so I can read the amplitude (current) off accurately. I did not have any anomalous results. I measured the current using an ammeter, as the voltage was to small to measure, and the amplitude (current) was whole numbers.
Here are the results that I collected in the main table. Theses are the results I will plot on my graph:
The results in red I think are anomalous results so did them again and put then into the table again. The results in blue are the averages; they have been affected by the anomalous results so I will have to work tem out again. This is what I got:
The results in red are the ones I did again. This time they have come out the same as the others. This also changed the averages, shown in blue.
Analysing and Considering Evidence
I have found out that when the ampage (current) increases the magnet becomes stronger and will hold more weights.
On graph 1 I have circled the anomalous results. I can tell they are anomalous by comparing the graph with graph 2. Graph 2 increases steadily in a straight line, it also levels out, graph 1 does not do this. I will analyse graph 2 as it is more accurate and has the anomalous results taken out.
Between 0 and 0.2 the magnet will not hold any weights, this is because the amplitude (current) is to low.
Between 0.2 and 0.6 this line on the graph is steadily increasing, this is because of the domain theory. When in a magnetic material all the atoms are arranged so that each side has an opposite polarity (North and South). In a material, which is not magnetic, these atoms are not arranged, therefore cannot pick up materials such as iron. In an electromagnet the higher the ampage supplied to a circuit, the more atoms are arranged. So it will gradually increase.
Finally between 0.6 and 1.0 the line levels out, this is also to do with the domain theory. When all the atoms are arranged, the magnet cannot become stronger.
So overall, as the magnet gets stronger, due to the increase in amplitude (current), it will hold more mass. Due to what I have said I have proven my prediction to be correct. This is supported by the domain theory.
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Evaluation
Anomalous Results
I have shown my anomalous results in my results table in the obtaining evidence part of my coursework. I then repeated my anomalous results and put then into a table again. The averages had been affected by the anomalous results so I worked them out again as well once I had retaken the anomalous results.
My results were as I expected them to be, once I had repeated the anomalous ones. I think my results are good enough to make a firm conclusion.
Problems
I could have used smaller mass weights instead of 100g weights, this would have given me more accurate results as I could have found how many I would hold to the nearest gram, this would also make the results differ more as there would be less grams so it might hold a slightly different amount each time .The only problem is that the school did not have 1 gram weights and it would have taken a lot longer to get the results.
Improvements
If I had more time I would take some more results after 1.0 amps to see if I have actually reached the magnets full capacity, to do this I would take readings from: 1.2, 1.4, 1.6, 1.8, and 2.0 Amps.
I would also retake 0.2 and maybe 0.1 with 1 gram weights to see how much they would hold, as they would not hold 100 grams, this would also make my graph more accurate.