Gauss Rifle Experiment
By Juliet, Kathrine, and Alyssa
Background Information | Problem | Review of Literature | Hypothesis | Materials | Set-Up
Procedure | Data | Conclusion | Return to Research Page
Background:
It was either the Chinese or the Greeks who discovered the properties of lodestone, which "contain magnetite, a natural magnetic material Fe304" (Jezek, 2006). This dated back to the first century, B.C. in the writings of Lucretius and Pliny the Elder, in which he mentions the "magical powers of magnetite." Years following, magnetite had been marked with superstitious feelings of possessing "magical powers, such as the ability to heal the sick, frighten evil spirits and attract and dissolve ships made of iron!" (Jezek, 2006). Magnets "attract paper clips, nails and other objects made of iron" (Giancoli,, 1998).
Johann Gauss, born April 30th, 1777, was a man or great accomplishment. Starting at the age of seven, "his potential was noticed almost immediately. His teacher and assistant were amazed when Gauss summed the integers from 1 to 100 instantly" (O'Connor and Robertson, 1996). Gauss built a magnetic observatory, completed in 1833 to observe magnetic declination. Gauss died in his sleep on February 23rd, 1855.
Statement of the Problem:
The purpose of this experiment is to find out the relationship between the spacing of the magnets in a Gauss Rifle and the velocity of the last ball, and use it to determine the maximum velocity that can be achieved.
Review of Literature:
Forces of magnets can "be either attractive or repulsive and can be felt even when the magnets don't touch" (Giancoli, 1998), which is an important part of the Gauss Rifle. Gauss Rifles are linear accelerators, in which "the kinetic energy of the ball is transferred to the magnet, and then to the balls touching it" (Field). We believe that there is a correlation between the spacing of the magnets and the final velocity of the last ball. The instructions we are using to create our Gauss Rifle say, "our one foot long version is designed so the speed is not enough to hurt someone" (Field), which indicates that the spacing between magnets will affect the velocity of the ball. In addition, an experiment testing the effect of magnet spacing in Gauss Rifles indicated that "the velocities increased as the spacing decreased" (Davis, 2003). This particular experiment was done "by testing spaces between 5 and 13 centimeters," (Davis, 2003) and we believe that with a larger range of spacing, we will find that the velocities resemble a bell curve when graphed.
Hypothesis:
We believe that the maximum velocity of the final ball leaving the rifle will be achieved by spacing the magnets neither too close nor too far away. This is because the magnets will be pulled together if they are too close, and the ball will lose velocity if the magnets are too far apart. Velocity is defined as the velocity of the final ball at the point of leaving the rifle.
Materials:
* molding with a right angle to use as a track
* 8 circular magnets, .8 cm in diameter by .5 cm in length
* 9.4 cm circumference steel balls
* molding clay
* scrap 2 by 4 wood
* 4 nails
* metal shelving track
* 1 sheet carbon paper
* several sheets of computer paper
* ruler
* tape
* miter saw
* hammer
Procedure:
Mark the molding with centimeter marks for later in the experiment. Cut one piece .53 meters long and cut another piece .55 meters long with one end cut at a 30 degree angle with a miter saw. Connect two pieces of wood into an "L" shape and save another scrap to support the end of the molding. Attach a shelving track to the "L" and to the scrap piece of wood to support the horizontal molding. Put some clay into the track and press the molding into it so it sits like a track. Put nails into the top of the "L" to hold the angled piece into place. The angled end should connect to the horizontal piece. Mark a line .515 meters up the ramp. Place the magnets on the horizontal piece starting with the first one 2 centimeters away from the end. This magnet should not be moved the entire time, however, the other magnets will be moved to the spacing desired (this is where the centimeters marked will help). Put tape around the magnets to hold them in place. Place two steel balls following each magnet (they should touch the magnet). Drop a ball from the line marked .515 meters up the ramp (always drop the ball from this point) and see where the ball hits the floor. This is where the paper and carbon paper should be placed, centered on this point. Measure the length between the edge of the paper and the point directly below the end of the apparatus. This measurement will be used later. Drop and reset the balls 12 times. These data points are recorded by the ball dropping on the carbon paper. Measure the points from the edge of the paper to the mark and add the length from step 5. Repeat the steps 3 through 6 for each of the spacings, from 3 cm to 12 cm.
Data: - Data File - (text - tab delimited)
# Spacing Avg Distance
Avg Velocity
1 3
37.017
8.424
2 4
44.842
10.205
3 5
42.992
9.784
4 6
40.725
9.268
5 7
34.200
7.783
6 8
32.517
7.400
7 9
32.392
7.371
8 10
30.850
7.021
9 11
24.517
5.579
10 12
21.325
4.853
Conclusion:
After gathering and analyzing our data, we calculated that our hypothesis was correct. We noticed that the peak velocity was achieved at the 4 cm magnet spacing. This was closer together than we initially anticipated, however, because our magnets were weaker than desired, it makes sense that a spacing farther than 4 cm weakens the attraction and slows down the velocity. There might have been a higher peak velocity between 4 cm and 5 cm spacing. However, we did not gather data in fractions of centimeters. As we graphed our data, we realized that the velocity jumped quite drastically from 0.8 m/s to 1.0 m/s, whereas after the peak velocity was reached the velocity would plateau the jump down, then plateau and jump down again revealing a step-like decrease in velocity as the spacing between magnets increased. We hypothesize that if we were to continue our data, the step pattern would continue until the velocity reached zero.
If we were to gather our data again, we would make a few changes in our setup in order to ensure more accurate data. First, we could have secured the base of the apparatus to the counter to ensure no movement of the apparatus during and after each trial. We also could have secured the ramp with something sturdier than clay. Lastly, we also noticed that the magnets would slightly shift due to the transfer of energy. But all-in-all the experiment was a success.
Links:
Charlene. "Magnets-How Magnets Work." 2006.
<http://www.geocities.com/SunsetStrip/Palms/8423/magnet.htm> . - For in formation on the history of magnets, how they work, and the uses for them today, this site is spectacular!!! :)
Davis, Michael. "California State Science Fair 2003 Science Fair Project Summary." 2003.
<http://www.usc.edu/CSSF/History/2003/Projects/S0204.pdf>
- Important to see how the acceleration in the accelerometer works.
Field, Simon. "The Gauss Rifle: A Magnetic Linear
Accelerator."
<http://www.sci-toys.com/scitoys/magnets/gauss.html> - This site shows the setup of the Gauss Rifle. :)
Jezek, Geno. "History of Magnets." 2006.
<http://www.howmagnetswork.com/history.html>- This site gives the history of magnets. :)
O'Connor, J.J. and E.F. Robertson. "Johann Carl Friedrich Gauss." December 1996.
<http://www-history.mcs.st-andrews.ac.uk/Biographies/Gauss.html> - A site giving the background of the man behind the Gauss
Rifle...Gauss himself!!!!!!!!!! :)
