By Mark Mabry, Head Teacher
East AM welcomed the addition of three little drawing “robots” to our classroom community this spring, constructed and introduced by one of our teachers. They were, in fact, simple electric circuits consisting of a battery, a small DC hobby motor and a switch, all connected with wires and mounted on a square of scrap cardboard no more than 6 inches across. The robots’ “legs” were washable markers, attached, with the tips pointing down, at each of the squares’ corners. The teachers wanted the robots to “dance” on the floor (with the marker caps on) or “draw” on paper (with the caps removed), so we attached small weights to the motor shafts to make the constructions vibrate and wobble. Children were able to playfully interact with these scribble machines while discovering more about the principles of a basic circuit: Power from the battery flows out of one end of the battery and continues along wires through the motor and back to the opposite end of the battery to complete an unbroken loop, which turns the motor. The concept of a switch is simply a means of breaking the electrical loop to turn off the motor and reconnecting it to turn the circuit on.
We wanted the children to be introduced to these machines and the workings of circuits not through a didactic lesson but through play, exploring what the machines can and cannot do, and noting the similarities and differences between them: the way they operate and move, and the different kinds of marks they leave on paper. We put faces on the robots and gave them names (HappyBot, Art and BabyBot) because we wanted children to engage with them in a whimsical way and relate to their “personalities.” We believe that young children discover scientific principles and understandings through hands-on, repeated experiences in a meaningful, playful context. For example, they learn intuitively in their play about the properties of balls and wheels on ramps without a teacher’s discussion of inclined planes. We were confident that the children's curiosity and experimentation would lead them to their own discoveries, observations, questions and theories.
We chose cardboard bases because we wanted children to interact with the robots not as intractable finished products, but as flexible, modifiable, and ultimately repairable devices once they inevitably broke down or wore out from repeated use. We also hoped that using a material that they were familiar with through their own constructions in the classroom would encourage confidence in their explorations of robot mechanics. Also, installing the components on a cardboard base allowed for fast prototyping when it came to building additional machines with the children—simple construction required only tape for connecting components and a pair of scissors for punching holes for the marker legs.
Parts and connectors for a drawing robot.
Although it could have been tempting to focus the children’s initial interactions on why these scribble-bots worked, explaining to them the principles of a simple circuit, we wanted them to explore how they worked instead. In watching how each of the robots moved within a table-top tray—especially when leaving traces of their movements on paper—the children became very knowledgeable about each machine’s unique characteristics. They began to predict the kind of marks that would be left, learned how to adjust the number of and orientation of the legs of each robot, and discovered how they could interact with and affect their movements (e.g., tilting the tray containing the paper, or lightly pushing or guiding the robot). They also became proficient at looking at a finished bot-art drawing and identifying which robot(s) had a hand (well, leg) in creating it: “BabyBot” tended to make circular patterns, “Art” did more bouncing—leading to drawing dotted lines—while “HappyBot” made smoother lines with sharp turns as it bounced off the sides of the tray.
Initially, a teacher’s presence at the table was quite helpful, showing children how to turn the robots on and off, helping them change out the markers for colors of their choosing, and facilitating turn taking. But by the end of the week, the children were switching out the legs carefully and independently, collaborating with others, sharing the machines and explaining to each other how to use the draw-bots without the need for much adult assistance.
With repeated experiences, children learned how to affect the movements of the machines by adjusting the heights and angles of the markers. For example, they very much wanted to have robots that drew circles and carefully watched and noticed that a robot with three legs, one slightly shorter than the other two, would pivot on the shorter leg while the other two markers would rotate around it. Children also began to make suggestions for modifications, such as attaching extra legs or adding cardboard “stabilizers” to keep the legs in the orientation they desired. In our explorations, children did begin to ask why the robots worked. These questions were often provoked by unexpected events, such as the battery vibrating its way out of the machine, or a loose wire somewhere in the circuit.
To answer such questions, we looked at the path of the wires connecting everything in a loop from one end of the battery to the other, perhaps interrupted by a switch that opened and closed the circle. BabyBot had the most basic switch: simply attaching one battery wire to the motor’s contact. To unbalance the motors so the robots would vibrate, we attached small weights (in the form of alligator clips) to the rotating shafts. When these inevitably fell off, we could see that the robot stopped moving entirely—until the clip was reattached. HappyBot also had a potentiometer (or as one child explained it to her father, the “volume”) added to its circuit, so that we could see how changing the speed of the motor affected the robot’s movements.
After playing with our original robots, we built a couple more, so the children could participate in the construction and see that there were many ways to go about making a drawing machine. At many children’s request, we also provided parents with directions and resources to continue their robot play at home.