There is a growing need for engineers in our ever changing world. NGSS engineering standards for middle school provide a framework for developing student understanding of the engineering design process.
This is a great lesson to remind students about electrical circuits. The Next Generation Science Standards have students exploring circuits in Grade 4 and not in middle school. This lesson gives students an opportunity to put into practice a skill they learned in Grade 4 so it remains fresh.
This is also a good lesson for developing "grit". The lesson does not provide students with correct, step-by-step instructions for creating and testing the scribble bot. There will be students who struggle, and you will want to encourage them to be persistent in problem solving. Engineering activities are about challenging students to work through the engineering design process until they are successful.
The longest part of the preparation is gather the materials for this lesson.
Each group of students will need two pieces of wire, about 10 cm long with the ends stripped. I do this ahead of time so we are not backed-up waiting to use the wire strippers.
I also gather materials to offset the motor. I look for odds and ends that can be placed on the motor shaft to cause it to spin off balance. This is what makes the scribble bot travel to create the interesting designs.
Students collaborate to design and build a scribble bot. (MS-ETS1.2 Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.)
Students are encouraged to modify their design so that each of the markers produces its own individual footprint. (MS-ETS1.3 Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.)
An important understanding for students in that engineering is an iterative process. They will design and test solutions multiple times. (MS-ETS1.4 Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.)
My student hook for this lesson is a sample of scribble bot art from a previous class. The class creates these works of art at the end of the scribble bot lesson. When students feel they have the best design for their scribble bot, they let the bot run for a few seconds on a large poster board or white paper. Their legacy is shared with the next class. I have also saved the paper drawings to use as wrapping paper!
The first thing we need to talk about it circuits. In the NGSS, circuits are covered in Grade 4 but I find that the time between Grade 4 and Grade 7 has some students needing a short refresher lesson.
I remind students that all parts of a circuit connect in two places. There are two wires on the motor and two wires on the battery. Student groups are given time to connect the wires and make the circuit.
We attach the motor and battery to the wooden craft stick. Students place these on top of the cups or main body of the scribble bot. The wire connecting to one end of the battery should be easy to connect/disconnect as this will be our on/off switch.
Normally, we want our motors to run smoothly. If our scribble bot has a smooth running motor, then it will not be able to create an interesting art footprint. Several odds and ends are provided for student experimentation. I include a lot of small rubber bands for students to use to attach items to the motor shaft. We also have some small gears, K'NEX pieces, foam, packing peanuts and other odds and ends to try.
The scribble bot can use up to three markers. Most student groups choose three different colors.
As you can hear in the video below, students are looking for ideas for continuous improvement of their bots!
When all students have had an opportunity to leave their scribble bot footprint, we wrap-up with a whole class discussion. The format of this discussion is organized around identifying the problem, constraints and criteria for success.
The purpose of this discussion is to continue to provide students with opportunities to hear and use the vocabulary associated with engineering. As we explore more engineering challenges, the expectation will be that students use the engineering content specific vocabulary as they work and communicate as engineers.
This lesson is so much fun that students ask if they can take photos and videos of their scribble bots to share.