Burlington middle-school tries to build prosthetic arm

Published 12:00 am Thursday, December 26, 2013

BURLINGTON (AP) — “It’s hard to make an arm,” said Nathan Ruhlman, seventh grader at Turrentine Middle School.
He would know. Nathan spent the past couple of weeks researching, designing and building a prosthetic arm with partner Ty’Rek Davis in Katie Zimmerman’s science, technology engineering and mathematics class.
Zimmerman’s two classes had to get a lot of background research in before they could dive into the project. They learned a lot about how the muscles in the human arm work and about prosthetics, and they even looked at how NASA built the robotic arm for the Curiosity rover on Mars.
Of course, the STEM classes could not work with titanium. Ruhlman and Davis worked with different sizes of PVC pipe, clear plastic tubing, pipe cleaners, straws and, of course, duct tape.
Emani Jefferies and Marco Bruno-Ruiz had paper towel tubes split down the middle and bound together with duct tape.
While they did not have to stay within a budget, students did keep a tally of the cost of their materials, Zimmerman said.
The test of the arms was lifting an empty plastic cup from the table with the arm attached to their shoulders.
The students had a lot of fun putting it together, but all faced frustration trying to get the finer points to work.
Ty’Rek was hanging his prosthetic from his shoulder with a loop of plastic tubing going around his neck. The attachment worked all right, but the pipe-cleaner-and-plastic straw fingers did not do as well.
“All I know is I can knock the cup over,” Ty’Rek said.
He ended up taking the straws off the pipe cleaners and experimenting with what shapes he could bend them into to get a grip on the cup.
Aryanna Baldwin and Timajawon Burton also used cardboard tubes for their arm, but attaching it to Timajawon’s shoulder was tricky.
Timajawon said there were no good materials for the job. The cardboard tubes were too narrow to go around his shoulder, and the wooden blocks would not bend around his arm.
Zimmerman offered no solutions, but asked questions. The students must be used to that because they did not seem particularly annoyed.
“How do you keep it from moving?” Zimmerman asked Nickola James, when her arm’s fingers kept pushing the cup instead of grabbing it. “What do you need?”
“A thumb,” Nickola said after a few more questions. “I don’t know how to make one.”
“Why don’t you try drawing the ideas,” Zimmerman said, and gave her some space to work on the problem and do some deep breathing.
Aryanna and Timajawon ended up splitting a cardboard tube and taping it around Timajawon’s arm, but it is uncomfortable. They ended up padding it with duct tape and foam packing peanuts.
Frustration is part of the lesson, Zimmerman said. It is important for her students to learn failure is not the end, but the time to rethink things and learn something.
None of the arms is done by the end of class, but there will be another.
And what did they learn?
“It’s hard to make an arm.”