Kinetic Sculptures: Working with Homopolar Motors
This week at University Settlement we challenged the group to create homopolar motors. Created in 1821, a homopolar motor is the simplest type of motor powered by electricity from a battery. The components of a homopolar motor are a AA battery, some disc magnets, and a long copper wire. The negative side of the battery is placed on top of the disc magnets and the copper wire is bent in such a way that it touches the positive side of the battery and the disc magnets simultaneously. This creates a direct current that powers a rotational movement, which we observe as the wire spinning around the battery. The students learned that homopolar means the same polarity. One magnetic field that does not change creates a Lorentz force. This is the force that is exerted by a magnetic field (disc magnets) on a moving electric charge (battery and wire).
The students had some frustration when trying to bend the wire in a way that would make it balance while spinning. Some students had trouble touching the wire to the top of the battery and to the magnets on the bottom, while at the same making sure the wire was a closed shape. The group was resilient though and pushed through the frustration and created kinetic sculptures by taping cut out magazine pictures and paper onto the wire. Through adding these paper objects we learned about weight distribution and balance when creating a moving object. The students were excited to see a static image became a moving object. One student utilized this by choosing a magazine cutout of a lion that also had a picture of a dolphin on the back. When it spun we saw both animals in rotation. Some students took a more comical route by taping pictures of local hero Lebron James onto the motor to watch him spin.
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We learned about direct currents and how movement changes the quality of static images. The group had a lot of fun putting images in motion and tinkering with the motor so that it could balance and spin without interruption.
