Andrew Shin

Jered Yagi

 

Mass and Surface Area effect on Magnetic Field

Table of Contents: Materials, Method, Data, Conclusion, Bibliography,

Go Up .:.

 

            Introduction

 

            What is a magnet? A magnet is a piece of material that has been magnetized. To tell if a material has been magnetized, one would test the magnetic field of the material. The most notable characteristics of a magnet are that it has two poles, north and south, and attracts or repels other magnets. Non-magnets do not attract other non-magnets, but non-magnets can be attracted to permanent magnets, like a piece of steel attracted to a fridge magnet. Permanent magnets create a magnetic field around them. An example of a permanent magnet is a whiteboard magnet. Magnetic fields are invisible lines of attraction between the two different poles of magnets. The strength of a magnetic field is exponential, so when you bring a south pole of a magnet 2 cm from a north pole of another magnet, you will have one-fourth the attraction of the same magnets when 1 cm away from each other. When you have the same magnets 4 cm away from each other, you will feel considerably less attraction. These magnetic fields are measured in the unit of Teslas. 1T is equal to 1Vs/m^2, where V=volt, s=seconds, m=meters.

            The purpose of this investigation is to explore how magnetic field is affected by the introduction of non-permanent magnets.

            We think that by introducing the mass of a non-permanent magnet to a permanent magnet, the magnetic field will decrease. We think this because we think that magnetic field will be distributed across more area, decreasing the concentration of magnetic field. We will test this by measuring the initial magnetic field output of a magnet at a certain distance, then adding masses of non-permanent magnets to the permanent magnet, while adjusting the combined masses to stay at the original distance. Mass will be measured in kilograms. Magnetic field will be measured in Teslas using a magna-probe.

 

 

Work Setup

UP .:.

        :)Materials

 

1 Magna-probe

1 giant magnet, when placed 15 cm from the magna-probe, it should read approx. 1.77 mT

3 1-kg ferrous metals

1 Standing Clamp

1 Roll of masking tape

1 Logger-pro program

1 computer + monitor + the keyboard + mouse

1 Chair

1 Notebook w/ paper

1 Pencil

 

UP .:.

        :)Method

            Start the experiment by turning the computer on and opening up logger-pro. Connect the magna-probe to the proper cables and set the magna-probe to magnetic field sensor on the program on the computer. Clamp the sensor on the magna-probe to the standing clamp. Place the giant magnet 15 cm from the sensor, make sure the magnet is level with the sensor. Use the tape as a raised base for the magnet if necessary. Take an initial reading with the logger-pro program. Highlight an area of points and then go to analyze and then statistics. Take the mean as your data point. Then attach a 1kg non-permanent magnet to the giant magnet.

 

Step 1

 

Step 2

Step 3

 

 

After you attach the first weight, again, take the Reading, average all the points and record your data.Then attach another weight to the side of the giant magnet. Again, take another reading, average the points and Record your data. Take your last weight and attach it to the opposite side of the second weight you attached. Take your last reading, average the points and record Your data.

 

UP .:.

       :)Data.

 

Our initial reading of the giant magnet at 15cm was 1.77 mT (miliTeslas).

 

Data file: text.:.Excel

 

Kilograms mT North mT South

 

4.6

0.1699

 

5.1

0.1567

0.1721

5.6

0.1596

0.1727

6.1

0.1552

0.1725

6.6

0.1535

0.1722

7.1

0.1503

0.1717

7.6

0.1475

0.1717

 

 

UP .:.

    :)Conclusion

Our hypothesis was correct to an extent. Our hypothesis was “We think that by introducing the mass of a non-permanent magnet to a permanent magnet, the magnetic field will decrease”. The non-permanent magnet did decrease the field and, except for the half a kilogram mass, the decrease was very linear. Our data indicates that the addition of non permanent magnet mass decreases the magnetic field concentration of a permanent magnet. Our test was inconclusive as to whether the overall magnetic field of the permanent magnet + non permanent magnet changed at all.

We think that the half kilogram weight’s was an outlier due to its surface area, or the errors that were listed in the results. Another test someone could perform would be to see how surface area contact between the additional mass of the non permanent magnet affects magnetic field. Could the difference of the surface area of the non permanent magnet and the size of the permanent magnet affect the absorption effect? During our research, we noticed that when we placed our non permanent magnets near the ends of the permanent magnet, the absorption effect was greater. This indicates that magnetic field is not evenly distributed throughout the mass of the magnet. This supports the idea that magnetic field tends to be polarized.

While doing our research, we came across a question as to whether magnetic field could be concentrated. As we were figuring out which masses would be most effective in our research, we used a flat, circular plate that we pounded with a hammer. What we ended up with was a radar dish shaped non permanent magnet. When we attached it to our giant magnet, we noticed a difference in magnetic field. When we compared the effects of the radar dish to the effects to a relatively flat plate of the same mass, the results were different. If we were to do another physics IA, a possible research question would be “Can magnetic field lines be concentrated to a focal point with the use of a radar shaped non permanent magnet?”

 

UP .:.

:)Bibliography  

http://galileoandeinstein.physics.virginia.edu/more_stuff/E&M_Hist.html

http://geophysics.ou.edu/solid_earth/notes/mag_basic/mag_basic.html

Knight, Jones, & Field, "College Physics" (2007)

Li Shu-hua, “Origine de la Boussole 11. Aimant et Boussole,” Isis, Vol. 45, No. 2. (Jul., 1954)

http://instruct.tri-c.edu/fgram/web/Mdipole.htm

 

Related Websites

http://science.howstuffworks.com/magnet.htm - This is the basics on how magnets work

http://en.wikipedia.org/wiki/Magnetic_field - This was helpful in explaining magnetic fields

http://www.physics.sjsu.edu/becker/physics51/mag_field.htm - Better understanding of magnetic fields

http://galileoandeinstein.physics.virginia.edu/more_stuff/E&M_Hist.html - Good for background infomation

http://en.wikipedia.org/wiki/Electromagnetic_field - A possible followup to the original using electomagnets