Teaching Simple Machines Through Afterschool STEM
Updated: 17 hours ago
AVI in Action | Weeks 5–7: Pulleys, Wheels and Axles, and Wedges
Agape had just demonstrated a chain reaction involving a ball, a track, and a cup that closed like a trap when a student from another site asked the question anyone who has built one of these projects would understand.
“How many times did y’all have to restart?”
“Many, many times.”
The students offered a couple of different estimates before explaining their materials and how long the project had taken. Among the pieces they had used was an old track. Something from an earlier build had found its way into the new design.
By Week 7 of Alabama Virtual Institute, students had several weeks of engineering experience to draw from. Their Afterschool STEM challenges had introduced different simple machines, with each project giving them another way to approach the semester’s larger Rube Goldberg challenge.
In our last AVI in Action installment, “When Students Have to Explain How It Works,” students were experimenting with ramps and levers and explaining the decisions behind their designs. Weeks 5 through 7 brought pulleys, wheels and axles, and wedges into the work.
Now, students had to figure out how those parts could work together.
From Pulleys to Wedges: Three Weeks of Connected STEM Challenges
Week 5’s pulley challenge asked groups to build a system that would respond to another object, such as a ball or domino, and lift something. Getting the pulley to move was part of the task. Students also had to decide what would trigger it.
The following week introduced wheels and axles. Groups were challenged to create a track for a toy car, with one condition: they could not simply push the car themselves. Something else had to set it moving. The lesson invited them to use their pulleys from the previous week.
Week 7 added a trap. Students were asked to use a wedge to help set off part of a chain reaction, perhaps by holding or releasing part of the mechanism. Earlier projects were again included among the materials they could use.
Week 7 at Comer Bridges (3rd/4th grade)
Week 7 at Comer Bridges (3rd/4th grade): a marble rolls down an orange track, knocks over a short row of dominoes, and lands in a cup at the end. The group explained that the cup works like a wedge, creating a dead end that traps the marble, and that a door-stop wedge at the start of the track adds incline. (4-second clip)
The weekly routine gave groups time to work through those decisions. Students began by asking questions, exploring examples, and planning a design. They then built, tested, and improved their projects before presenting them to other sites.
For educators planning a series of STEM activities, that continuity is worth considering. A new challenge can give students a reason to revisit something they already understand while asking them to use it differently. In AVI, the track from one week could become part of the next week’s reaction.
What Students Kept From Earlier Designs
During Coosa’s presentation, an AVI educator asked whether the students had built everything that week or continued from a previous STEM project. The students confirmed that some of their construction came from earlier work.
It was a brief exchange, but it answered a question I would want to ask when looking across several weeks of student projects: Where is the earlier learning showing up?
At Agape, students pointed to an old track among their materials. At Coosa, a student explained a sequence in which a ball would reach the dominoes, the dominoes would hit a car, and the car would strike a support beneath a container. Several parts had to respond in order for the design to do what the group intended.
That gives an educator something specific to ask about. Which part had already worked in an earlier project? What needed to change when it became part of this one?
Those questions can help distinguish between reusing a material and understanding how to use it. A student might keep a track because it is already built, then discover that its position or ending needs to change. Asking about that decision brings the conversation back to the problem the group is trying to solve.
It also gives students credit for work that may be difficult to see in a finished photograph. The current design has a history, and its builders can help explain it.
Peer Questions Made the Engineering Easier to Follow
Students had a role in one another’s presentations. Sites helped count down demonstrations, watched the reactions, and asked questions afterward.
At Agape, the audience wanted to know how often the group had restarted, what materials it used, and how many days the project took. When Agape’s students watched another group present, one asked how they had come up with the design.
At Coosa, a question about how the project was made prompted a step-by-step explanation. The student walked through what would hit what and how the action would reach the support beneath the container. An AVI educator responded by noting how clearly the student had explained the process.
That kind of explanation gives other students a way into a complicated project. They can follow the intended sequence and ask about a particular connection instead of trying to make sense of everything at once.
For educators, it also creates an opportunity to listen for understanding. Can students explain what starts the reaction? Do they know which part needs to move next? When something stops, can they identify where it happened?
One question I would carry into a similar activity is, “Which connection are you going to watch most closely this time?” It asks students to make a decision before the next test. Afterward, they have a specific place to begin discussing what happened.
Resilience Included Deciding What to Change
The social and emotional learning themes followed the demands of the projects.
Week 5’s “Flip the Script” discussions asked students to think about changing their approach. Week 6 focused on resilience, including how groups make decisions when people disagree. One discussion prompt invited a site to share a problem and ask another site for advice.
Week 7 turned to feeling stuck and facing dead ends. Students were asked how they handle starting a project over.
Anyone who has guided a group through a hands-on challenge knows how quickly those questions can become relevant. One student wants to keep adjusting the original design. Another wants to take it apart. Both may have reasons, and the group still has to decide what to try with the time available.
Week 7 from BAMA KIDS (grades 3–5)
Week 7 from BAMA KIDS (grades 3–5): a row of dominoes falls and sends a ball toward a cardboard box set up as the trap. The group shared this clip with the note “Our first try wasn’t a success.” (6-second clip)
The planning made room for those conversations alongside the engineering work. Students were being asked to consider how they responded to problems and how they worked with other people when a solution was not obvious.
Agape’s “many, many times” answer fit naturally into that discussion. The repeated attempts were part of what students shared with their peers about building the project. A useful next question would be what changed between those attempts.
For a group that is stuck, that is where I would begin: “Show me what happened last time. What do you want to try differently?”
Giving an Unfinished Project Another Chance
Near the end of one elementary session, Holt’s third graders were still working to get their project ready.
Educators checked back several times. They offered the option of posting a video to Padlet and let other sites know they could leave if they needed to. They also stayed available for Holt to present live.
Some sites remained. Eventually, another countdown began, and Holt demonstrated a sequence that drew comments about its trap door and long stretch of dominoes.
I appreciated the patience in that exchange. The students had more work to do before they could show the project, and there was a way for them to come back when they were ready.
That is a practical consideration for Afterschool program leaders planning presentation days. A group may need another turn, a little more setup time, or the option to share a video later. Building in one of those options gives students a way to finish sharing their work without holding every other group to the same schedule.
Across these three weeks, AVI’s challenges gave students reasons to return to earlier ideas and consider what they could do with them next. Their presentations gave educators and peers opportunities to ask about those decisions.
At Holt, that meant staying through a few more resets. When the third graders were finally ready, other students were still there to count them down.
Learn More
When Students Have to Explain How It Works: Read the previous AVI in Action installment about ramps and levers in Weeks 3–4.
AVI in Action: When a Chain Reaction Has a Job to Do: Follow students’ earlier work with dominoes and purposeful chain reactions.
Alabama Virtual Institute and CAMP Programs: Learn more about CAMP’s approach to STEM and social and emotional learning.
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