I spent most of Saturday at the Fort Worth Museum of Science and History for Engineer’s Week. I sat at a table with half a dozen kids at a time, showing them how to connect little DC motors to batteries, and exploring and explaining series and parallel connections for the braver ones. We had several DC motors with a glue stick off center on the shaft of the motor so it would wobble, and velcro attached the motor and battery holder with alligator clip leads to a scrub brush. The result was a giant hex bug popping around on the table. Some kids were very interested in how they could take it further, and others had glazed expressions. For the ones that wanted to go further, I showed them how to connect three 9V batteries in series to feed the motor 27 volts… and it really buzzed. Then I told them we were on the Mars Rover team and had to make sure that even if a lead broke, the rover would still go. And so we connected them in parallel. They seemed confused by the fact that even though there were 3 batteries like before, it was going only as fast as one battery. I explained that the trade-off was reliability in case one of the batteries failed, and that with 3 batteries in parallel, the motor would run 3 times as long at 9V. The most fun was watching them experiment. I also swapped the leads on the motor and asked them if anything was different. About 70% of the kids noted that it turned in the opposite direction; one decided that it was going faster. I didn’t give hints; I just kept holding the motor while they swapped leads on the largest motor running on 1.5v so it was slow enough for them to see, although it was still going quite fast. I let them take as long as they needed. The expression in one girl’s eyes, in her face as she concentrated, told me her future. She was intrigued, and determined to see what I saw and know what I knew. I do believe that she would have swapped leads for 15 minutes if it had taken her that long. I spoke to her mom, who happened to be a chemical engineer. And she promised me that yes, she saw it, too.
I wish all kids had the opportunity to get one-on-one time with a motor and had someone to explain it in simple terms to them. About 90% of the kids that sat down at my table were intrigued about solving problems and had the patience to figure out what was different when they swapped leads. I think that solving puzzles and patiently digging until you find the answer is the most vital trait a would-be engineer can have. How many of us actually use all of the things we learned in college? Mostly, I think they taught us the basics, how to learn, and how to solve problems. They taught us to think like engineers. They taught me that math is the language of engineering, and once I saw this, I was humbled by the enormity of what it meant; that expressing physical phenomena in mathematical terms is truth, and universal. If intelligent aliens exist in other galaxies, they are at least governed by the same physical laws as we are, and undoubtedly they also have a means of expressing the same physical laws with math. This is why science, engineering, and math are so special. Not only do we work with truth, we share that truth with the universe.
Lynnette Reese holds a B.S.E.E from Louisiana State University in Baton Rouge. Lynnette has worked at Mouser Electronics, Texas Instruments, Freescale (now NXP), and Cypress Semiconductor. Lynnette has three kids and occasionally runs benign experiments on them. She is currently saving for the kids’ college and eventual therapy once they find out that cauliflower isn’t a rare albino broccoli (and other white lies.)
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