a working railgun not only converts potential energy to kinetic energy but also takes advantage of Newton's third law to shoot a steel ball-bearing using magnets dr. Smith is going to use a total of 13 steel ball bearings to 24 inch long 1/2 inch inner diameter PVC pipes tape measure for neodymium magnets electrical tape and scissors to make his railgun he places the PVC pipes alongside one another and attaches the first neodymium magnet six inches from the end of the combined pipes notice what happens when he aligns three steel bearings on one side of the magnet and rolls a fourth ball bearing toward the other side of the magnet potential energy gets converted to kinetic energy as the bearing increases its speed as it gets attracted to the magnet and as it travels toward the magnet when it strikes the magnet its momentum gets transferred to the last steel bearing which shoots off at a much faster speed than what the initial ball bearing was rolling with a railgun takes advantage of this conversion of potential energy of the magnets to kinetic energy of a ball bearing he is now placing a second neodymium magnet four inches from the first magnet check this out this time when he rolls a bearing toward the combined magnets the final bearing shooting out of the rail gun is even faster so now he's going to place the third and fourth magnets on the gun separated by about four inches the combined potential energy of the magnets converts a slowly rolling ball bearing into a bullet to increase the power of the railgun make sure the magnets are oriented such that they are attracting one another you can also increase the length of the PVC tubes and separation of the magnets for increased power