Simple, Affordable Speaker

For our physics project, we made a portable speaker out of simple, household objects! You can attach it to any MP3 player or connect it to an amplifier to make a louder speaker.

• Three paper plates
• Magnet(s) (we used three neodymium magnets)
• Alligator clips
• Enameled coil wire
• A sheet of paper
• Tape (or hot glue)
• An old pair of headphones (for the plug)

Wrap paper around the magnet(s), making sure to give enough room for the magnet(s) to easily slide in and out of the paper cylinder. Tape the paper.

Once this is complete, tightly wrap the wire around the paper, but leave the ends of the wire unwrapped. Make sure the magnet(s) can still move in and out of the paper easily! Secure the coil by gluing or taping it to the paper.

Cut off the extra paper you don't need.

On the middle of a plate, glue/tape down the roll of paper. Then attach the magnet(s) to the middle of the other plate. You can glue/tape them down, but we decided to use an adhesive magnetic strip to secure them.

Make sure the magnet(s) and roll of paper are lined up!

Cut up the remaining plate into two strips, and then fold them accordion style. Glue/tape down the strips to both plates, making sure they are an equal distant from the magnet(s) and paper.

Strip the ends of the coil wires and then connect those ends to the alligator clips.

Cut off the head phone plug and strip off the material covering the wires. Connect the alligator clips to these wires.

Plug in your speaker and you're finished!

When you place your ear right above the top plate, you can hear the music clearly and feel the vibrations. Add an amplifier and you can hear the music while sitting next to the speaker. You can also test your speaker by playing a frequency sweep on YouTube.

Physics explanation: The speaker works because alternating current flows through the enameled coil wire and is attracted or repelled by the neodymium magnets. Then, variations in amplitude and polarity when placed close to a stable magnetic field will make the plate vibrate. The vibrations will generate sound waves we can hear when the enameled coil wire is attached.