Gauss Rifle

The Gauss rifle or coilgun was first designed in 1904 by Kristian Birkeland.  Electromagnetic weapons are designed as an alternative to conventional firearms, by removing the need for cartridges and explosive power to propel projectiles. Coilguns use coils of wire that have current running through them to create a magnetic field that moves the projectile down the barrel. The coils either come in multiple stages or one continuous one. This project will demonstrate the properties of magnetism and kinetic energy. The Gauss rifle in this experiment uses a multistage design and no coils, but the principle is the same. The magnetic attraction pulls the projectile to create kinetic energy and then that energy is added to each stage, accelerating the projectile. 
Driving Question: How does a Gauss Gun work?

  • A wooden ruler
  • 4 1/2" magnets
  • 13 3/8" steel balls
  • tape
1. Place the first magnet at the 2.5-inch mark of the ruler and the rest 2.5 inches apart (make sure the magnetic poles face the same way), then secure them in place with tape.

2. Add 3 steel balls to the same side each magnet on the ruler, making sure they are in the same direction.

3. To fire the rifle, quickly push one steel ball towards the end without the balls until the magnet attracts it. One ball from each pair should shoot towards the next magnet and cause the same to happen to the next.
-Flying projectiles, eye protection may be needed.
-Keep electronics away from magnets.
-Magnets may pinch fingers, gloves may be necessary.


The Gauss Rifle works by using kinetic energy and magnetism. The kinetic energy of the first ball is transferred to the magnet and then on to the balls on the end of the magnet. Then that last ball on the end of the magnet shoots towards the next magnet and the same thing happens, but the magnetic attraction increases the speed of the ball, thus increasing the kinetic energy being sent. This is why the more magnetic sets are added, the farther the last ball flies. However, the steel ball will eventually travel so fast that the next magnet it hits will shatter. 

One would be looking at this project and wonder, what magnets shooting balls have to do with real life. Well, the Gauss Rifle in this project is a basic model of a coilgun. A gun that uses magnetism to accelerate a projectile instead of powder. Currently, coil guns are built by hobbyists who like to build things and the military is also experimenting with this system to launch mortars. In the future, soldiers may become stealthier, and the risk of hearing loss may be reduced. Besides weaponry, the principles of the Gauss rifle can be seen in particle accelerators, which are large hollow loops that use many strong series of magnetic coils to accelerate particles to such speeds that they separate into sub-particles and collide to make new atoms. These devices are used in physics research that may one day bring about an improved source of energy, or give us more knowledge about certain phenomena like black holes and pulsars. This project could have presented the connections better by using higher quality materials and construction with better precision, but this was a very simple demonstration that can be done at home.

Would it be possible to make the reaction more intense?
Absolutely, you can either add more sets of magnets and make the rail longer, or you can use larger magnets and steel balls. Keep in mind that the material used to make the magnets may not withstand the impact at a certain point.

Can the materials be substituted?
The railing can be substituted with any leveled, non-magnetic material. The balls can be replaced with other metal balls, but keep in mind that not all metals are ferromagnetic, but as long as it contains enough iron, nickel, or cobalt, it should be fine. Other magnets may be used such as the black ones used to hold things on the fridge, but the advantage of neodymium magnets is that they have a high amount of strength and compact size, which means less energy is lost through the magnet.

How do magnets work?
Magnets work because they have a magnetic field, which is an invisible field that is represented in layers. This is due to the arrangement of the atoms and the ratios of subatomic particles within them. Magnetic fields occur naturally or are artificially created by running an electric current through a wire. Some objects can become temporary magnets and will show the properties of a magnet but become weaker over time.

What effects do the magnets have?
The magnets in this project are very important. The effect demonstrated is similar to Newton's cradle, in the fact that kinetic energy is transferred to the next object. Unlike Newton's cradle, it does not lose energy because the magnets have a magnetic force which pulls and adds on to the kinetic energy of the ball so it does not lose energy and instead, goes faster. The stronger the magnet, the faster the balls will become in each sequence.