Build the World's Simplest Electric Train

Materials you'll need

• 20 gauge copper wire
• Wooden dowel
• Blue painter's tape
• 1 AAA battery (fresh)
• 6 neodymium disc magnets

 

Step-by-step tutorial

Step 1: Tape one end of the copper wire securely to a wooden dowel to anchor it in place.

Step 2: Spin the dowel to wind the copper wire tightly around it, coil by coil, keeping each loop snug against the last. Keep turning until you have at least 5 inches of coil.

Step 3: Slide the finished coil off the dowel and gently stretch it out so there's a small, even gap between each loop.

Step 4: Divide your neodymium magnets into two stacks of 3. Hold the stacks face-to-face and find the orientation where they push each other apart — that's the correct setup. (Tip: like poles should face outward on each end.)

Step 5: Press one magnet stack onto each end of the AAA battery so they stick firmly to the positive and negative terminals. This battery-and-magnet combo is your "train car."

Step 6: Gently place the train car into one end of the coil and watch it zoom through! For non-stop action, bend the coil into a circle so the battery zips around and around. Note: don't let the battery run for more than a few seconds at a time as it can get warm.

Learn more

This project runs on electromagnetism — the force created when electricity and magnetism team up! When the train car sits inside the coil, the neodymium magnets touch the bare copper wire and complete an electrical circuit, causing current to flow through a short section of coil. That flowing current turns those few loops into a tiny solenoid — a coil-shaped electromagnet — with its own north and south poles. The magnetic field then pushes the magnet at the front of the battery and pulls the magnet at the back, launching the whole train forward. As it moves, a new section of coil powers up and the push-pull cycle repeats, propelling the train all the way around the track. This awesome hands-on experiment is something you can do for a science fair project.