John Merila of Nevis High School finished 2nd place overall at Bemidji State University Regional Science Fair on Saturday, Feb. 13. For his project Merila constructed an electromagnetic rail gun; more commonly known as an EMRG. An EMRG is a projectile launcher that uses parallel conductors or “rails” to accelerate a conductive projectile between the rails using electromagnetic effects. Initially, it was Merila’s intention to see how the railings would affect the speed of the projectile - a small aluminum rod shot out at a very low velocity.
According to Merila, when the electrical current goes through the projectile there is force outward onto the rails rather than the recoil firing back as it would with a rifle or handgun. Therefore, firing the rail gun requires much more structural strength to keep the rails together. The rails are made out of a conductive metal such as copper and coated with various types of materials to prevent friction between the projectile and the rail. Merila acquired a capacitor and then built a charging circuit to be able to charge it using a 12-volt battery; commonly used in depth finders. Through the charging circuit he charged the capacitor to the voltage necessary then was able to run that to the rails using extension cords. In a previous project he had used a higher voltage capacitor, which proved to be more dangerous.
“To keep it safe, I decided to test the lower voltage,” Merila explained. At Nevis schools where Merila is currently a sophomore, 7th and 8th graders are required to participate in the science fair as part of the regular curriculum. When Merila was in 8th grade he went to state on a similar project to his this year. Merila did not compete at the event last year because he was unable to complete his project in time. “I wanted to do it because it was just something cool to do,” Merila said when asked why he chose this particular project. “I read things about other people who had made them (EMRG) and it sounded like something cool that I could build that wasn’t too complex but still showed complex physics.”
Merila has always loved physics and figuring out the intricacies.
“It sounded like a cool concept to see the physics behind it and you can actually see the physics,” he said.
Currently the U.S. Navy is researching the use of EMRGs in a much larger scale as a weapon that would use electromagnetic forces in the magnitude of thousands of volts, rather than explosives. NASA has also proposed using rail guns to fire payloads into orbit, which would greatly reduce the cost. However, there are limitations. According to Merila, using an EMRG for small scale applications would not be feasible with current electrical technology because the electrical current required to make it useful could potentially be dangerous to the user.
In April, Merila will advance to Minnesota State Science & Engineering Fair in Minneapolis. He is also the alternate to the 2016 Intel International Science & Engineering Fair to be held in Phoenix, Arizona in May 2016; which is the highest anyone from Nevis has ever advanced. Merila also won cash prize from 3Suns School of Engineering and Applied Science for outstanding work entered in the science fair. Next year, Merila would like to expand on this concept.
“I’d like to see if a higher voltage capacitor would work on any of the railings I’ve already constructed,” he explained. “To see the effect of different lengths of rails on the velocity of the projectile to see if it is linear or exponential. “And I’d like to learn more about what goes on in the process. There’s a lot more behind it that we currently don’t understand.”
In the future Merila would like to continue participating in the science fair in the hopes of earning a college scholarship to further his studies in physics and possibly engineering.