Giving 5th Grade a Hand

This STEM lab rotation find the 5th grade faced with an engineering design challenge. We do a lot of work with the design process in the lab, and even when it is not the focus, it is at the heart of every unit. 

The first part of the process is to understand the task. That includes making observations and gathering information through research. I did not tell the groups what the challenge would be at the start of the unit. However, I did tell them that we would be building several models of mechanisms that move. I also let them know that these activities were meant to provide them with information and ideas they could use for the challenge.

The first make was a two fingered pincher similar to one people use to reach objects on the ground without having to bend over. The two fingers are attached to a piece in the center that the user pulls back bringing the fingers together. Conversely, pushing the center piece forward forces the fingers open. Next, students used card stock paper and brass fasteners to make a scissor mechanism. This is an excellent device for extending the reach of something. Several students had seen the scissor lifts frequently used to reach light fixtures in rooms with high ceilings. Finally, the students made a model of their own hands with independently controlled fingers. Short lengths of straw were attached between each of the joints of the fingers as a stand in for the bones. A string was threaded through each straw and attached to the tip of each finger to mimic the actions of muscles and tendons contracting to pull the fingers closed. Each build was accompanied by a descriptive journal entry of their observations on the device's function and possible uses.

At the start of week two, I introduced the building challenge: design and build a device that can individually pick up a tennis ball, golf ball, cotton ball, and plastic cup and drop it into a bucket. The device must be operated from a distance of at least 24 inches from the objects being picked up. Groups were limited to using a meter stick, cardboard, string, tape, and a few toothpicks or bamboo skewers to make their device work. They started by brainstorming solutions and planning in their journals. Once that was done, they were allowed to start building and testing. Throughout the unit, many groups attempted to make a scaled up version of one of the previous week's models, and some succeeded in doing so. However, the most successful devices were those that adapted the designs in some way. Not every groups was successful, but in the STEM lab that is OK so long as students can articulate why they failed and how they might improve their design given more time. 

I had not done this unit for a couple of years, but I love it because of the variety of designs students create that all complete the same task. It is so important for students to see and to experience that for many questions or problems there are many correct solutions.

It's Time to Light the Lights

For their second turn in the lab, fourth grade is taking their knowledge of circuits to the next level using the Raspberry Pi computer. During their classroom science lessons on electricity and circuits, students learned to create complete pathways for electricity using regular light bulbs and D-cell batteries. In this unit, they used the kinds of electromechanical components employed by digital makers, LEDs, breadboards, resistors, and tactile buttons.

We started by spending a couple of days getting acquainted with these new components. Students built simple circuits using a battery pack and an LED. Then they added a button that could be used to turn the light on when it is pressed and off again when it is released. They had a good deal of time to experiment and tinker adding more LEDs. An interesting discovery many students made is that the LEDs require slightly different voltages so depending on how the circuit was set up, some lights would not light together. My favorite part of this segment of the unit is, after getting all 4 of their LEDs glowing, the teams start clamoring for more lights.

After learning to control their circuits mechanically (with moving parts like a button), students moved to the Raspberry Pi stations to learn how to take control digitally (with computer code). They started by using an add on board called Traffic HAT. Traffic because it is a set of 3 LEDs in red, yellow, and green resembling a stop light, and HAT for Hardware Attached on Top. This saves them from the distraction of learning a new way of wiring the LEDs while also learning the programming constructs that are used to control the circuits. The versions of Scratch that are embedded in the Raspberry Pi operating system have extensions that allow for physical computing (using a computer to control or gather information from physical components like LEDs, motors, buttons, and sensors). This is my favorite part of the entire unit solely because of the excitement that sweeps the room as LEDs begin to blink. What inevitably follows is students tinker with their code creating new effects, then call out to their neighbors to show what they have done.

Next, after becoming comfortable with the coding and still using the Traffic HAT, students use a breadboard and wires to add a button that they can use to control their LEDs. They also learn that the button can be used to make things happen on the computer screen. It can make characters talk or move, backgrounds can be changed, and just about anything else they can imagine. After that, I remove the Traffic HAT and provide students with a box of components like those they used at the beginning of the unit so that they have to build all of their circuits from scratch. Their final task for the unit is to create a game of some kind that uses at at least two LEDs and one button. I provide them with a guide for making a multiplication facts game, but they have the freedom to make any kind of game they want. Some make the math game, while others make quizzes about dinosaurs, Texas history, or Pokemon.

As always, I have been genuinely impressed by all of the creative ways the students have applied their new physical computing skills to the creation of projects that represent their interests and personalities.