I will make sure that I keep the same variables because this could affect my experiment and give me different results that I should expect.
I did preliminary work before doing the investigation such as going onto the Internet for appropriate information on electromagnets. I was able to print some information out that was essential and also looked at diagrams which helped my understand more about electromagnets.
The websites I went onto were:
I also looked at books, which we use during the class to look up on the topic, and to see if they had any diagrams that I could have included with my coursework.
Apparatus:
- Power pack
- Two crocodile clips
- Wire (for the coils)
- Paper clips
- An iron bar magnet.
Step-By-Step Method:
- I firstly set up the power pack; making sure it was on two volts
- I then placed both crocodile clips in the black and the red hole on the right hand side of the power pack.
- I clipped one crocodile on one side of the wire and the other on the other side.
- I then wrapped the wire around the iron bar magnet.
- I began creating my coils.
- I first started with five coils and then went up in fives until 25.
- I will make sure I put the power pack on two volts.
I will do the investigation three times for more precise and clear results.
Fair Testing: To make sure my investigation is a fair test I will keep these things the same:
- Iron bar magnet
- Length of wire
- Sized volt
- Power pack
The only thing I will change is:
- The amount of coils on the iron bar magnet
Diagram:
Results:
My results show that as increased the amount of coils the amount of paper clip picked up also increased. My results show that the results differed when I repeated the test again.
Conclusion: My prediction was correct that by increasing the number of coils the more paper clips the iron bar magnet picked up. This was because when the electrical current flowed through the coil wire, a magnetic field was produced around the coil wire. When the electrical current flowed through the coil wire, the weak magnetic field was concentrated therefore that the coil behaved like a magnet. When I switched the current on the coil it will pick up the paper clips. I wanted to strengthen the magnetic effect of the coil, so I increased the number of coils. This allowed the iron bar magnet to pick up more paper clips because the field around each of the coils contributed to the total magnetic effect.
Analysing: After studying my graph I realised my prediction was correct. My scatter graph showed that as the number of coils increased, there was an increase in the amount of paper clips that were picked up by the iron bar magnet because my graph showed positive correlation. My graph also showed that my points had strong correlation because the points all lied close together to the line of best fit.
My graph was steeper at the end of the experiment than at the beginning because as I increased the amount of coils on the iron bar magnet the greater and stronger the magnetic field was becoming around the coils this then helped pick up more paper clips then at the beginning when there was less coils.
My noticed that my first set of results slightly differed from the second and third time. I repeated my experiment three times to make sure that I got the correct and accurate results and in doing so I would get an precise average. I realised my results must have been approximately correct as I did not discover any anomalous result.
Evaluation: My investigation went very well. I had systematically planned my method and followed the instruction I had written down therefore; I got the results that I expected. To improve my method to get better results I could clearly state in much more detail what tasks need to be carried out and how they can be carried out. The method is the main element in the experiment therefore needs to be designed to help the user. The instructions need to be clearly stated therefore the user can comprehend the full experiment and know what they have to do. You also should be repeating the experiment at least two to three times to get more accurate and legible results. Also, form these results you can work out an average of your results.
I did not discover any anomalous result, which hopefully meant that my experiment went according to my plan.
My results were reliable because they proved my prediction to be correct. In my prediction, I said that that by increasing the number of coils the more paper clips I would be able to pick up with the iron bar. My results showed that each time the coils were increased the amount of paper clips picked up increased too.
I could carry out some other investigations to see if the results differ to the result I have. I could also see if the magnetic effect of the coils can be increased by
- Increasing the size of the current flowing through the coil. This would increase the strength of the magnetic field around each length of the coil wire
- Placing an iron core inside the coil. This would concentrate the magnetic field into a magnetic material, increasing the overall magnetic effect of the coil.
