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Rail Gun


A high-amperage power source is connected to two metal rails and the circuit is completed with a metal rod perpendicular to the two rails. Two large magnets are set at one end of the track then generate a magnetic field which is used to start the rail gun.


To demonstrate Lortentz force and the application of the right-hand rule.


Provided with the demo:

  • Rail gun tracks
  • Steel rod

Kept elsewhere:


  • Place two square horseshoe magnets with the south pole on the bottom in the slots provided at starting terminal of the rails. Place them so that the 'mouths' of the magnets are pointing down the track.
  • Connect the leads of the power supply to the demo, ensuring the left starting terminal is connected to the positive lead.
  • Place the rod on the rails in the opening of the horseshoe magnets. Make sure the rod is placed perpendicular to the tracks 1)
  • Set the power supply to the desired setting. Setting the powerstat to 60 seems to work well; higher and the arcing gets worse and the rods sticks to the track. Lower and the rod will roll slowly or not at all.
  • Turn the power supply on and watch the rod travel across the rail as it arcs and sparks.


While the voltage across the rails is relatively low, there is a very high amperage flowing across them so burns are a potential hazard. Note that as the rod rolls it'll produce a shower of sparks; this could present a fire hazard if there's anything easily combustible nearby.2)

Demo room information

Location OPQ0
Maker Unknown
Current State Working
The rod should be aligned with the L-shaped connectors on either side of the rails.
Things like tissues, spilled ethanol, etc.
demonstrations/5_electricity_and_magnetism/5h_magnetic_fields_and_forces/rail_gun/start.txt · Last modified: 2020/01/28 18:38 by demoroom