Linzel Magnet Field Lab Report1/16/2018 Introduction: Tostart off, Electromagnetic induction is when there is a change in magneticfield strength, which then causes electrons to shift, leading to an electriccurrent. Electromagnetic induction is found in motors, generators, as well asinductors. When the strength of the magnetic field changes, this causes achange in voltage, or an electric current. For our experiment, the magnetsmoving through the coiled wires in the solenoid served as the change inmagnetic strength. Each time the magnet entered the coils, thus entering themagnetic field, it would send off a charge, and each time the magnet exitedfrom the coils thus exiting the magnetic field, it would send out anothercharge, causing the change in the levels of voltage.
The reason that thisoccurs is because the entering of the magnetic field causes a shift in theposition of the electrons, causing the charge to be sent out. When the magnetthen exited the field, the electrons shifted again, returning to their originalstarting point. The shifting of the electrons is what causes the levels ofvoltage to rise, and fall. In our lab report, we were testing how the levels ofmagnetic strength or the number of magnets affected the levels of voltage,which are determined by the readings of millivolts on the millimeter. Coulombslaw states that the attraction or repulsion of a charge directly comes from ifthe charge is positive or negative. His law also states that in order for thecharges to be attracted to each other, they must have opposite signs, and ifthey have the same charge, then they repel each other. Hypothesis: As the number of magnets being passed through thecoils of wire increases, the strength of the magnetic field will increaseexponentially, thus causing an exponential rise in the voltage levels. Variables: Type What it is Unit of Measurement Independent Variable The number of magnets moving through the coils, altered by adding two magnets each time in order to see the difference in voltage.
Number of magnets Dependent Variable The levels of voltage, as shown on the multimeter. This is measured in millivolts. Millivolts Controls: Controls Why should it be controlled? How should it be controlled? Number of coils If the number of coils that the magnet was being pushed through was different, this could change the strength of the magnetic field, therefore affecting the levels of voltage. This number of coils was kept constant; we did this by ensuring that the magnet did not touch the coils.
In our experiment, we made sure that there were 5 coils of wire the entire time. Size of coils If the size of coils that the magnet is being pushed through was different in each experiment, this could change the strength of the magnetic field. The size of the coils was kept constant, we did this by ensuring that the magnet did not touch the coils, which coil have changed the shape of the coils, or could have led us to having to reform the coils. Speed of magnet movement If the speed of the magnet varied, this could change the strength of the magnetic field, because the coils get a charge every time the magnet enters, and leaves the magnetic field. This happens because the entering, and leaving of the magnetic field causes a shift in the electrons, generating energy. This was mainly kept constant, as I attempted to wave the magnet through, pause for a second, and then wave the magnet through the coils again. Setting on the multimeter (measured in millivolts) This is essential because the setting on the multimeter could affect the levels of voltage.
This was kept a constant by making sure that we stayed on the same setting throughout the experiment. Same wires connected to the coils If there were different wires connected to the coils, this could change the reading of voltage that the multimeter generated, because the wires are connected to the multimeter. This was kept a constant by making sure that we finished our experiment in one class, thus ensuring that we were using the same wires throughout the experiment. Each magnet was tested for the same amount of time (3 seconds) If the magnets were tested for a different amount of time, this could change the experiment, because not each magnet would have the same amount of time to reach its highest possible voltage level in that time allotted. We made sure to use a stop watch to ensure that we were testing each magnet for the same amount of time. Highest voltage reading on the multimeter This is important, because the multimeter is rapidly changing, constantly showing different levels of voltage, by using the highest number that the multimeter uses, we can ensure that we are not randomly choosing a number to represent that test. This was kept a constant by ensuring that we chose the highest number that showed up on the multimeter.
Procedure: First, we tested how magnets affected, orchanged the strength of a magnetic field. To set up the experiment, my partnerand first cut a piece of wire, and bent it into five coils of equal size, andheight. We then sanded the edges of the wire, to make sure that there was noplastic on the edges of the wire, where the clams connected to the wire. We didthis to make sure that the plastic would not act as an insulator. We then setup the multimeter, which had red and black probes that went into it. The blackprobe goes into the “COM” setting, and the red probe goes into the “VQMA”setting, which is used to measure voltage. After that, we took the end of theblack probe that did not go into the multimeter, and attached a clamp to thatwith one end of the clamp attached to that, and the other end of the clampattached to the edge of the wire. We then did the same thing with the redprobe, attaching a clamp to the edge that did not go into the multimeter.
Thesame clamp that was attached to the red wire was also attached to the coil. Bynow, everything should be linked together, forming a circuit in which the voltagecharges could travel through. After this was done, we set the multimeter to themillimeter setting, and kept the multimeter on this setting for the entireexperiment. After the circuit was set up, we started testing. We tested 5different values, 5 times, resulting in a total of 25 tests. To start off, westarted with two circular magnets, and we tested the amount of voltage theseproduced.
Once you have tested the two magnets twice, you can add two moremagnets, and once again test how four magnets affects the levels of voltage.For the third test group, we tested four magnets, we tested 8 magnets for thefourth test group, and finally, 10 magnets for the fifth test group. In orderto hold these magnets, and allow us to move them through the coils swiftly, wehad to hold these magnets with tweezers, meanwhile holding down the edge of thewire, so that the magnet did not get attracted to the wire, and stick to it,messing up our data results.
Having the magnets in tweezers, and the wire helddown, we then proceeded to move the magnet between the coils, causing themagnet to enter, and then leave the magnetic field. One partner was moving themagnets in and out of the magnetic field, paying close attention to the time,and the other was watching the multimeter, looking for the highest reading. Mypartner and I made sure to always take the highest value that showed up on themultimeter, helping us keep our data collection constant. After each test, wetook note of the values we got, and put them into a data table.
These numbersshould be reproducible if these steps are followed correctly. The data table isbelow. Data Table: #Of Magnets Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Average Standard Deviation 2 1.2 1.0 1.2 1.1 0.
7 1.04 0.207 4 3.6 3.8 4.8 6.
1 6.7 5.00 1.372 6 6.
6 7.2 8.3 7.5 7.5 7.
42 0.614 8 8.7 7.4 8.5 9.
4 7.4 8.28 0.870 10 10.9 10.
4 10.3 9.6 9.8 10.
20 0.514 Limit of Measurement:Accuracy of the voltmeter is plus or minus 0.71 Analysis: Lookingat the data we got, as well as the line graph we were able to make with ourdata, it is pretty evident that the data is rather linear.
The biggestdifference comes from test group one to test group two, where the voltagelevels increase from 1.04 millivolts all the way up to 5 millivolts. Afterthat, the data is quite linear, resulting in a linear change overall, as wellas a graph that would make one interpret that voltage levels were supposed toincrease through a linear change. Although in our hypothesis, we believed thatthe exponential change in magnetic field strength would result in anexponential change in voltage levels, the data would suggest otherwise. Describe Data: Inour experiment, to start off, you can see that with two magnets, the averagereading on the multimeter is a voltage level of 1.04 millivolts.
In ourhypothesis, we claimed that we believed that there should have been anexponential rise in voltage levels, due to there being an exponential increasein field strength. However, in the second test group, we tested four magnets,and that got an average reading of 5 millivolts. At this point in time, mypartner and I think that there is a possibility for an exponential increase involtage, due to the numbers that we have. However, as we kept going, test groupthree came out with an average voltage of 7.24, test group four came out withan average of 8.28, and test group five came out with an average of 10.20.After looking, at this, it looks like the increase from having two magnets, tohaving four magnets caused the greatest change in field strength, resulting inthe biggest jump in voltage levels to occur.
If you look at our data as anoverall, it looks pretty linear, suggesting that an exponential change inmagnetic field strength does not mean an exponential change in voltage levels. Explain Data: Throughoutthe data, you can see one major trend, and that is the linear change thatoccurs in the voltage levels. If I was to use the data I see in order to form anew hypothesis, I would believe that the change in magnetic field strength doesnot have an effect on the levels of voltage, regardless of what I believedbefore this experiment. I believe this because, you can see in the data thatthe only exponential increase was at the beginning of our experiment, when thevoltage levels jumped from 1.04 up to 5. After that, the increase in voltagelevels flattened out, showing a linear change in the voltage levels throughoutthe rest of the experiment.
I believethat the reason that magnetic field strength does not have an effect on whetherthe voltage levels are exponential or linear because, the change in the voltageis caused from a shift in the electrons when the magnet enters, and exits themagnetic field. This would mean that there reaches a limit, where the electronscan no longer shift very quickly, causing the levels in voltage to flatten out. Judge: Based onthe hypothesis my partner and I came up with, I firmly believe that the data wecame up with was not the best representation of what truly happens when anincrease in magnetic field strength occurs. On top of that, the error bar for thisdata was quite high, showing that this data may not be all that reliable.However, this experiment was one that was quite complex, and the readings thatwe got relied upon the circuit, and making sure that everything was maintainedconstant. Slight changes in wire connections, or slight changes in coil size,or coil shape, could cause us to get a very different reading than the others.Because of this, I am quite happy with the data I collected. The room for erroronly became an issue as I hit tested groups two and three, and then went backdown from there, making me believe that the room for error was caused by thereadjustment of the coil that we were forced to do after test group two.
Thisdata shows, and follows a clear trend, thus making me believe that this is anaccurate representation of what happens with voltage levels, and also leadingme to believe that if our experiment was reproduced, those doing so would comeup with similar numbers. Conclusion: Thepurpose of this experiment was totest how a magnet entering and exiting a coil of wire, changing the strength ofa magnetic field, affected the levels of voltage that were shown on themultimeter. My partner and I believed that the exponential change in the magneticfield strength would then in turn cause there to be similar exponential changein the voltage. Based on the data that we collected, and the constant linearchange shown throughout it, I believe that the hypothesis that me and mypartner came up was not supported. I believe this because there is a clear, andconstant linear change shown in the line graph, not the exponential increasethat we had first believed would occur as the magnetic field strengthincreased.
If I think about why this may be, I simply believe that voltagelevels hit a point where they can no longer increase greatly, and thereforeflatten out into a linear increase over time. The reason I was led to thatconclusion is because in data tests one and two, there seemed to be a linearchange, satisfying the hypothesis that my partner and I had come up with,however, once we kept going, we saw that the change in voltage levelsdecreased, and got closer and closer together, before taking a slight jump fromdata test four to data test five. Although the data that we collected does notsupport our hypothesis, I believe that we collected quality data, that showsthe true relationship between magnetic field strength, and voltage levels. Evaluation: Althoughmy partner and I did not collect data that supported our hypothesis, overall, this experiment was quitesuccessful, and I was able to improve my knowledge around magnetic fields, andvoltage. The experiment went quite smooth, and my partner and I were one of thefirst groups to be done, due to the simplicity in what we were changing, andtesting throughout the experiment.
My partner and I tested how the change in numberof magnets would influence the voltage levels. The only issue with this was thenumber of magnets we decided to test. If I was to go back, I would have asmaller increase in magnets, to see if this showed the change in voltage levelsoccurring differently. I would also change the number of magnets that we testedand have my tests be of one magnet, two magnets, three magnets, all the way upto five magnets for the five test groups, rather than having my test groupshave two magnets, four magnets, six magnets, all the way up to ten magnets.
Thereason for that is because it was hard to have ten magnets at the same time,and test it, while still allowing all the other groups to have enough magnetsto do their experiments. Another change that I would make would be to make thecoils bigger, and wider in order to ensure that the magnets would not hit, ortouch the wire, deforming it in any way, or even causing us to have to try andshape the wire back into a circle. I think one other thing that we could haveimproved upon, was just making sure that the magnets were entering, and exitingthe magnetic field at the same rate in each trial. Because that was hard to do,and not something that my partner and I had really thought about something thatwe had to keep constant, there were slight changes in speed of the magnet, aswell as different amount of times that I would pause before pushing the magnetsback through the magnetic field. The differences in time and speed could havecontributed to a high error bar. Looking back at our error bars, I notice thatas the test groups go higher up, there tends to be a higher error bar.
Ibelieve the reason for that is because I came into the experiment believingthat there would be and exponential change, and therefore, I could havepossibly altered the speed at which I was moving the magnet through the coil,looking for higher numbers to satisfy my hypothesis. Next time, I will try tobe more conscious about the fact that my beliefs may have caused me to possiblyalter, or attempt to skew the data in a direction that the data would not haveoriginally gone to. Once again, I really enjoyed this experiment, and I was quitehappy with the data that we got as an outcome of our tests. Bibliography Citation: Bertans, David. Columbus Law.
Unknown, 12 Apr. 2013. Das, Tanumay. Faradays Law. India, 21 June 2014.