The Anatomy of a STEM Test Stand

A test stand is a piece of equipment that engineers build in order to test a design, or to make design decisions. If you are using Project Based Learning in your STEM classes, a test stand can make the Engineering Design Process come alive! Examples of test stands you may have used are:

  • The sizing rig used to test the diameter of the capsule in an egg-drop project
  • The Drop Station used to standardize the drop distance in an egg-drop project

Our STEM club built cardboard pinball games this semester and we built a test stand to determine the ideal spring and balls for the shooter apparatus. The pinball project spanned six club meetings and consisted of five mini-challenges:

  • Design and build a shooter. The shooter is the spring-loaded plunger that fires the ball up into the playing field.
  • Design and build the playing field.
  • Design and build flippers to keep the ball in play.
  • Build and place obstacles.
  • Design a scoring system.

Since the very first challenge was to design and build the shooter, teams needed a way to test their ideas and make changes before they got too far along in building their games. To get ideas for their shooters, teams observed small handheld pinball games from Amazon so they could understand how the spring and plunger were arranged. Then they built their prototype shooters on a piece of cardboard. We provided three different weights of compression springs and three different kinds of balls. The test stand allowed them to try out different variations of their designs before the game board was ever set up.

The goal for the test stand was simple: make an enclosure that could keep balls from flying around the room and allow teams to measure the effectiveness of their different designs. We used a utility table (30” x 60”) as the platform and covered the surface with cardboard. To keep the balls under control, we added cardboard walls on both sides and one end. The walls were 24” high. We added a meter stick to one side of the test stand so teams could make consistent measurements. The meter stick could be repositioned so that teams could set it to start at the end of their shooter. We also added a clip-on utility light, so teams could make good observations.

The test stand turned out to be a big hit with the teams. The kids had fun and there was lots of innovation and variation from one team to another. In the course of 90 minutes, all six teams had shooters that worked, and they were excited to move on to the next challenge. In your next PBL, consider adding a simple test stand to the classroom hardware. By giving students a way to test drive their ideas, you’ll generate excitement and give the teams a way to engineer a well-tested solution.

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