6th Grade:

Tiny Dancers

Homo-polar motors-the first, simplest electric motor!

INTRODUCTION:

Tiny Dancers are simply a dressed up homo-polar motors, which are the simplest kind of electric motor causing continuous circular motion. To make your own homo-polar motor all you need are a few easy to obtain items fun item as a great introduction to electricity and electromagnetism.

Tiny Dancers.mp4

MATERIALS:

Copper Wire
1/2″ x 1/8″ Neodymium Disc Magnets
AA Battery
pliers/wire cutters
Template
Crepe Paper (optional for skirt)
Hot Glue (optional)

SAFETY PRECAUTIONS:

* THE MOTOR CAN GET HOT! The wire and battery can get very hot so handle with care.

* Neodymium magnets are extremely strong and MUST BE KEPT OUT OF REACH OF SMALL CHILDREN! Do not give them to any child who might put them in their mouth, they are dangerous if swallowed and must be surgically removed. Additionally neodymium magnets can interfere with electronic devices so please keep them away from phones

STEM PRINCIPLE and Uses:

A homopolar motor is basically a device that converts a magnetic field and a direct electric current into motion. Our copper wire is conducting electricity from one end of the battery to the other. As current moves through the magnets on the negative side of the battery, it creates a magnetic field which causes the wire to spin. Scientist Michael Faraday first demonstrated this effect in 1821 using a wire rotating around a magnet in a mercury bath. Although the simple ones we make here aren't practical for doing work, they are great for demonstrating the concept of electromagnetic forces and explaining the concepts behind how motors work. Early homopolar motors during the 20th century were used in ship propulsion. Since then electric motors have evolved much more complexity and are used in m

PROCEDURE:

You can find diagrams of how the wire needs to be bent HERE and other pictures and tips at THIS WEBSITE.

Cut a long piece of wire off your spool, I started with about a 10” long piece. Lay it on the template of your choice and bend as shown using 3-in 1 tool or pliers. No need to be perfect HOWEVER try and keep your form as symmetrical as possible.
To create the base section of wire that wraps the magnets, I recommend bending the end of the wire around the battery. Remove the battery and gently widen the circular wire form with your fingers.
Place three neodymium magnets on the negative side of your battery.
Place the bent wire on top of the battery so that it touches the positive pole. The round section at the bottom of the motor must be low enough to encircle the magnets!
Let it go. If properly constructed it should start to spin. If it doesn’t visit the website linked above. They have helpful tips.
(optional) to make a skirt for your dancer cut a small circle of crepe then cut a slit in the center of the circle. Slide it up onto the dancer and secure in place with a dab of hot glue.

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