# Carter the strength of the magnetic field will

Carter Mott

Mr. Linzel

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Magnet Field Lab Report

1/16/2018

Introduction: To
start off, Electromagnetic induction is when there is a change in magnetic
field strength, which then causes electrons to shift, leading to an electric
current. Electromagnetic induction is found in motors, generators, as well as
inductors. When the strength of the magnetic field changes, this causes a
change in voltage, or an electric current. For our experiment, the magnets
moving through the coiled wires in the solenoid served as the change in
magnetic strength. Each time the magnet entered the coils, thus entering the
magnetic field, it would send off a charge, and each time the magnet exited
from the coils thus exiting the magnetic field, it would send out another
charge, causing the change in the levels of voltage. The reason that this
occurs is because the entering of the magnetic field causes a shift in the
position of the electrons, causing the charge to be sent out. When the magnet
then exited the field, the electrons shifted again, returning to their original
starting point. The shifting of the electrons is what causes the levels of
voltage to rise, and fall. In our lab report, we were testing how the levels of
magnetic strength or the number of magnets affected the levels of voltage,
which are determined by the readings of millivolts on the millimeter. Coulombs
law states that the attraction or repulsion of a charge directly comes from if
the charge is positive or negative. His law also states that in order for the
charges to be attracted to each other, they must have opposite signs, and if
they have the same charge, then they repel each other.

Hypothesis: As the number of magnets being passed through the
coils of wire increases, the strength of the magnetic field will increase
exponentially, 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, or
changed the strength of a magnetic field. To set up the experiment, my partner
and first cut a piece of wire, and bent it into five coils of equal size, and
height. We then sanded the edges of the wire, to make sure that there was no
plastic on the edges of the wire, where the clams connected to the wire. We did
this to make sure that the plastic would not act as an insulator. We then set
up the multimeter, which had red and black probes that went into it. The black
probe 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 the
black probe that did not go into the multimeter, and attached a clamp to that
with one end of the clamp attached to that, and the other end of the clamp
attached to the edge of the wire. We then did the same thing with the red
probe, attaching a clamp to the edge that did not go into the multimeter. The
same clamp that was attached to the red wire was also attached to the coil. By
now, everything should be linked together, forming a circuit in which the voltage
charges could travel through. After this was done, we set the multimeter to the
millimeter setting, and kept the multimeter on this setting for the entire
experiment. After the circuit was set up, we started testing. We tested 5
different values, 5 times, resulting in a total of 25 tests. To start off, we
started with two circular magnets, and we tested the amount of voltage these
produced. Once you have tested the two magnets twice, you can add two more
magnets, 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 the
fourth test group, and finally, 10 magnets for the fifth test group. In order
to hold these magnets, and allow us to move them through the coils swiftly, we
had to hold these magnets with tweezers, meanwhile holding down the edge of the
wire, 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 held
down, we then proceeded to move the magnet between the coils, causing the
magnet to enter, and then leave the magnetic field. One partner was moving the
magnets 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. My
partner and I made sure to always take the highest value that showed up on the
multimeter, helping us keep our data collection constant. After each test, we
took note of the values we got, and put them into a data table. These numbers
should be reproducible if these steps are followed correctly. The data table is
below.

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: Looking
at the data we got, as well as the line graph we were able to make with our
data, it is

pretty evident that the data is rather linear. The biggest
difference comes from test group one to test group two, where the voltage
levels increase from 1.04 millivolts all the way up to 5 millivolts. After
that, the data is quite linear, resulting in a linear change overall, as well
as a graph that would make one interpret that voltage levels were supposed to
increase through a linear change. Although in our hypothesis, we believed that
the exponential change in magnetic field strength would result in an
exponential change in voltage levels, the data would suggest otherwise.

Describe Data: In
our experiment, to start off, you can see that with two magnets, the average
reading on the multimeter is a voltage level of 1.04 millivolts. In our
hypothesis, we claimed that we believed that there should have been an
exponential rise in voltage levels, due to there being an exponential increase
in 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, my
partner and I think that there is a possibility for an exponential increase in
voltage, due to the numbers that we have. However, as we kept going, test group
three came out with an average voltage of 7.24, test group four came out with
an 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, to
having four magnets caused the greatest change in field strength, resulting in
the biggest jump in voltage levels to occur. If you look at our data as an
overall, it looks pretty linear, suggesting that an exponential change in
magnetic field strength does not mean an exponential change in voltage levels.

Explain Data: Throughout
the data, you can see one major trend, and that is the linear change that
occurs in the voltage levels. If I was to use the data I see in order to form a
new hypothesis, I would believe that the change in magnetic field strength does
not have an effect on the levels of voltage, regardless of what I believed
before this experiment. I believe this because, you can see in the data that
the only exponential increase was at the beginning of our experiment, when the
voltage levels jumped from 1.04 up to 5. After that, the increase in voltage
levels flattened out, showing a linear change in the voltage levels throughout
the rest of the experiment.  I believe
that the reason that magnetic field strength does not have an effect on whether
the voltage levels are exponential or linear because, the change in the voltage
is caused from a shift in the electrons when the magnet enters, and exits the
magnetic field. This would mean that there reaches a limit, where the electrons
can no longer shift very quickly, causing the levels in voltage to flatten out.

Judge: Based on
the hypothesis my partner and I came up with, I firmly believe that the data we
came up with was not the best representation of what truly happens when an
increase in magnetic field strength occurs. On top of that, the error bar for this
data 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 that
we got relied upon the circuit, and making sure that everything was maintained
constant. 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 error
only became an issue as I hit tested groups two and three, and then went back
down from there, making me believe that the room for error was caused by the
readjustment of the coil that we were forced to do after test group two. This
data shows, and follows a clear trend, thus making me believe that this is an
accurate representation of what happens with voltage levels, and also leading
me to believe that if our experiment was reproduced, those doing so would come
up with similar numbers.

Conclusion: The
purpose of this experiment was to
test how a magnet entering and exiting a coil of wire, changing the strength of
a magnetic field, affected the levels of voltage that were shown on the
multimeter. My partner and I believed that the exponential change in the magnetic
field strength would then in turn cause there to be similar exponential change
in the voltage. Based on the data that we collected, and the constant linear
change shown throughout it, I believe that the hypothesis that me and my
partner came up was not supported. I believe this because there is a clear, and
constant linear change shown in the line graph, not the exponential increase
that we had first believed would occur as the magnetic field strength
increased. If I think about why this may be, I simply believe that voltage
levels hit a point where they can no longer increase greatly, and therefore
flatten out into a linear increase over time. The reason I was led to that
conclusion is because in data tests one and two, there seemed to be a linear
change, satisfying the hypothesis that my partner and I had come up with,
however, once we kept going, we saw that the change in voltage levels
decreased, and got closer and closer together, before taking a slight jump from
data test four to data test five. Although the data that we collected does not
support our hypothesis, I believe that we collected quality data, that shows
the true relationship between magnetic field strength, and voltage levels.

Evaluation: Although
my partner and I did not collect data that supported our hypothesis, overall, this experiment was quite
successful, and I was able to improve my knowledge around magnetic fields, and
voltage. The experiment went quite smooth, and my partner and I were one of the
first groups to be done, due to the simplicity in what we were changing, and
testing throughout the experiment. My partner and I tested how the change in number
of magnets would influence the voltage levels. The only issue with this was the
number of magnets we decided to test. If I was to go back, I would have a
smaller increase in magnets, to see if this showed the change in voltage levels
occurring differently. I would also change the number of magnets that we tested
and have my tests be of one magnet, two magnets, three magnets, all the way up
to five magnets for the five test groups, rather than having my test groups
have two magnets, four magnets, six magnets, all the way up to ten magnets. The
reason 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 magnets
to do their experiments. Another change that I would make would be to make the
coils bigger, and wider in order to ensure that the magnets would not hit, or
touch the wire, deforming it in any way, or even causing us to have to try and
shape the wire back into a circle. I think one other thing that we could have
improved upon, was just making sure that the magnets were entering, and exiting
the 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 that
we had to keep constant, there were slight changes in speed of the magnet, as
well as different amount of times that I would pause before pushing the magnets
back through the magnetic field. The differences in time and speed could have
contributed to a high error bar. Looking back at our error bars, I notice that
as the test groups go higher up, there tends to be a higher error bar. I
believe the reason for that is because I came into the experiment believing
that there would be and exponential change, and therefore, I could have
possibly 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 to
be more conscious about the fact that my beliefs may have caused me to possibly
alter, or attempt to skew the data in a direction that the data would not have
originally gone to. Once again, I really enjoyed this experiment, and I was quite
happy 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.