Kids engineer cardboard prosthetic arms in Silly Science finale


The Spencer County Public Library hosted its last Silly Science program for the summer, though plenty more activities are scheduled to take up the afternoon time slot. Teacher Shelby Sitzman focused last Tuesday’s activity on engineering, explaining how string and tension can be used for various mechanical functions. In this case, Sitzman demonstrated how a few household items can build a rudimentary “robot arm” capable of lifting small objects.

After an enthusiastic parting paper towels from their cardboard rolls, kids had the “arms” necessary for their new tools. The tricky part was creating the “fingers” and getting them to work. By threading a string through small holes in straws, tension could be applied by tugging a string and causing one end of the straw to bend. With enough straws tied to a single string threaded through the cardboard tube, one pull can cause all straws to “grasp” after a fashion. While the end products were understandably flimsy, kids were mostly able to articulate their creations and take hold of some small stuffed animals. 

Sitzman left the students with a take-home project that some surely found even more exciting, a project kit for a home catapult made of spoons and other household materials. She cautioned, however, that projectiles should be limited to soft objects that won’t threaten any mishaps with fragile surroundings.

Photos and story by Don Steen


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