Sampling simple machines
By DAVID GREEN
Make no mistake about it, if you’re a third grade student in Lori Garrow’s class at Morenci Elementary School, you’re going to learn about simple machines.
This year brought a bonus, however.
After lunch Monday, students turned their attention to a television screen at the front of the room, ready to spend an hour with Professor Gadgeteer from COSI.
By linking up for a video conference, students watched the professor in action from her lab in Columbus, Ohio, while she, in turn, saw the students via a camera mounted on a classroom TV.
Students prepped for the presentation by working through a couple of lab sheets involving the Happy Crab.
The Happy Crab is a small red windup toy, a crab with a happy face that dances when set loose on a table top.
It’s not just a toy, Prof. Gadgeteer pointed out. It’s a gadget—something incorporating at least a pair of simple machines.
Students studied the crab’s movements, thought about how it was able to move and took guesses about what was inside.
They also performed a series of tests in preparation for the long-distance learning day. Predictions were made about the number of wind-up turns and the resulting time in motion. Comparisons were made between the crab’s motion on the table and its motion while holding it off the table.
Prof. Gadgeteer wanted to know what the students thought was inside the crab, then she led them through a review of simple machines.
“How many of you guys jump on your bed?” she asked, leading into a discussion about springs.
A screw is a cylinder with an inclined plane, she said.
“If you look under your chair, you’ll see a lot of screws holding it together.”
Everyone suddenly disappeared as they bent down to take a look.
Pulleys, wedges, wheels and axle, levers, gears, eccentric wheels—there are many simple machines that help people with everyday tasks.
It was time for some reverse engineering, Prof. Gadgeteer said. Rather than designing a gadget, the students would tear one apart to find out what makes it tick—or in this case, how it dances and waves its arms.
The class was divided into four groups with tasks assigned to each members. The Project Leaders went to Mrs. Garrow’s desk to obtain a Happy Crab. Each Structural Engineer loosened a screw and handed parts to a Materials Handler.
Students eventually got to the guts of the gadget and the simple machines were identified. The professor mentioned that Mrs. Garrow could help them put the gadgets back together later—that caused some raised eyebrows from the teacher—because it was time to move on to the Chattering Teeth.
This was another wind-up gadget students were called on to guess what made it worked. Then it was time to tear it apart.
The toy contained an impressive collection of simple machines—six in all. Once they were recorded, reassembly was needed.
Alex Thomas and Sierra ••• had their teeth chattering in no time with for a successful completion of the project.
The hour was up and it was time for the professor to leave. She showed off her Bell Bopper, a not-so-simple set of simple machines used to turn off her alarm clock, and then the show was over.-February 14, 2007
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