Use The Forces!

This rotation of STEM Lab finds the second graders exploring forces and motion by building mazes and marble runs. This is one of those experimental units that I implement from time to time. As a result, each group's experiences and projects were a little different as I tweaked and adjusted based on how well various activities went in previous interactions.

The unit began with students recording some simple observations in their journals how a marble rolls around in a paper box lid with some straws taped to it. I gave them some starter questions, 'how does the marble move when the box is flat? When you tilt the box?' and so on. We discussed their observations and then did some research into force and motion with Brain Pop Jr. Students took notes in their journals about words like motion, position, and force. We discussed how these terms related to their observations.

The first build of the unit was a marble maze using Lego bricks. A Lego plate is, of course, covered with bumps which effects how the marble rolls. This gave us the opportunity to talk about friction and how a rough surface is not as good for rolling objects. What I have ended up loving most about this part of the unit is how creative the students were with their mazes. I saw mazes not just with dead ends, but traps that it was impossible to escape. There were tunnels and bridges. Some mazes had checkpoints that had to be reached in a certain order. Several had the kind of elaborate back stories that second graders specialize in telling. Sure, they learned about the pull of gravity and how the walls push back on the marble to stop it or change its direction, but the creative expression was the biggest win.

The second build brought us back to cardboard box lids and straws as we shifted to making marble runs instead of mazes. The first time through this part I learned the distinction between a "maze" and a "run" was not clear to a number of students. This became evident as the first batch of attempts had dead ends that prevented the marble from reaching the bottom of the box. A bit of explanation and the added constraint that their runs could not have straws that the marble does not touch, and the results improved dramatically. Students were challenged to make runs that used a certain number of straws and that took certain amounts of time to complete the course. I have been really impressed by how the students problem solved for the different design requirements.

There are definitely some things I would adjust about this unit, like additional building materials, surfaces, and marble sizes in order to more deeply examine the effects they have on the outcomes observed. Overall though I am fairly pleased with how this went and I look forwards to its next iteration.