Marble Coaster - STEAM Design PBL Unit

As a STEAM Design teacher, I work with fifth and sixth graders in our school's STEAM Lab and Maker Space. In this environment, students are encouraged to engage in tinkering, creating, and engineering activities that promote creativity and problem-solving skills. We run a nine-week unit where each class is 48 minutes long, and students come to my class every other day.

The project I'm about to describe spans multiple classes, but it can be adjusted to suit different schedules. I got the idea from an Instructable, which led me to discover Tinkercad. I have since adapted this idea for my classroom. In this project, students apply the engineering design process to construct their own marble rollercoasters. It's a great opportunity to foster collaboration and communication among students.

I've included the project requirements and the scoring rubric that I use to evaluate the students' marble coasters.

Tools:

Tinkercad

Calipers

Original Prusa i3 MK3s+ 3D printer

Scissors

Hot Glue Guns

Color Printer

Table Saw

Drill

Rulers

Mega Blocks or any building item

Materials:

cardboard

straws (paper and/or plastic)

1/8 dowel rods

popsicle sticks

tongue depressors

various colors of construction paper

marbles

craft materials of your choice

I introduced this project to my students and explained how for the next couple of weeks they were going to be using the engineering design process to create their marble coasters. The students were encouraged to think about their own experiences on rollercoasters and what they liked and didn't like about them. Every child tends to have an opinion about rollercoasters. The kids who love them, are excited to design and create their own, and for the students who don't like I introduced this project to my students and how they would use the engineering design process to create marble coasters over the next few weeks. I encouraged them to draw inspiration from their personal experiences with rollercoasters, focusing on what they enjoyed and disliked. This approach excited the rollercoaster enthusiasts, who were eager to design their coasters, while reassuring those less fond of them, that they wouldn't have to ride their creations.

Next, I introduced my students to Tinkercad, a 3D design website, and taught them about prototyping. Over three classes, we covered the basics of Tinkercad through various simple projects. In the fourth class, I introduced calipers, enabling students to design Tinkercad objects that they could compare to real-world items. Our first exercise involved replicating a Mega Block in Tinkercad, matching the dimensions of the physical block they held.

Once the students were comfortable with Tinkercad, we started prototyping their marble coasters. They used virtual equivalents of real materials available in our Makerspace, such as straws, dowel rods, popsicle sticks, and cardboard. To expedite the process, I used Tinkercad's classroom function to distribute a pre-made design featuring these materials. The students then began the exciting task of designing and planning their marble coasters in Tinkercad.

After completing their marble coaster designs in Tinkercad, students printed images showing different orthographic views. These served as building plans for their physical marble coasters. I emphasized that the Tinkercad design might not precisely match the final product, which is perfectly fine. Flexibility and creativity are key during the building and engineering design process.

Each student received a 12x12 inch cardboard piece, into which I drilled a hole at a corner, similar to the prototype in Tinkercad. This hole is where the marble should exit. Students were encouraged to choose a theme for their coaster, though it wasn't mandatory to incorporate this theme in the Tinkercad prototype. By allowing them to pick their themes, I aimed to foster natural engagement with the project.

The students were tasked with decorating the cardboard's base in a way that matched their chosen theme. They could use various materials such as construction paper, craft supplies, or printed images from the internet. I encouraged them to unleash their creativity and enjoy the process.

After the students have covered their cardboard bases with theme-related items, they move on to constructing track supports, known as T-supports. For this, we use 1/8-inch dowel rods and popsicle sticks. I provide them with various measurements for these T-supports. The students understand that controlling the marble's speed is crucial, so the T-supports are designed to gradually decrease in size. We implement a consistent half-inch decline for each T-support, which effectively prevents the marble from moving too quickly. Many students have taken the initiative to experiment with different sizes of T-supports. This experimentation allows them to vary the speed along different sections of the marble coaster, creating areas of faster movement and others where the marble slows down. I encourage this creative exploration and also suggest that they try constructing T-supports using different materials.

Using their orthographic plans and built T-supports, the students began placing the first supports on the cardboard base, starting at the top of the track. I demonstrated how to hot glue straws onto the T-supports, ensuring a path for the marble to roll. It's crucial to space the straws correctly: too close, and the marble easily falls off; too far apart, and the marble either drops through or stops at a T-support. I also explained how one track segment leads the marble to the next, facilitating a hands-on understanding of the Laws of Motion, momentum, inertia, kinetic, and potential energy. These moments, when the marble either rolls smoothly or encounters problems, spark valuable discussions and discoveries about these scientific principles. As the students witness these concepts in action, their learning becomes more tangible and engaging. Continuously, they add more T-supports and straws, working downwards to the base of the cardboard, and testing the functionality after each new section is added.

Over several classes, the students continue the engineering of their marble coasters. They enhance their designs by adding more T-supports and straws, always guided by the engineering design process. My role involves frequently reminding them to test their projects. This step is crucial because there's a specific time requirement for the marble's journey, which they often overlook. I make rounds in the classroom, timing each student's marble to ensure it doesn't reach the end too swiftly.

A common tendency among the students is to aim to complete the entire project before initiating any tests. I have to emphasize to them that testing can, and should, be integrated at any stage of the engineering design process. Delaying tests until the end makes it challenging to implement changes to the coaster. In contrast, regular testing during the building phase enables immediate, impactful adjustments. It also provides valuable insights into the overall functionality of the design.

Interestingly, the marble itself turns out to be the most effective teacher. Through testing, it reveals the strengths and weaknesses of the construction, guiding the students towards necessary improvements.

Students keep adding tracks and theme-related items until they fulfill all the building criteria. They conduct tests to ensure the marble takes sufficient time to reach the hole in the cardboard. To foster creativity, they are encouraged to embellish their tracks and base with theme-related items. I provide approximately 60 varied craft materials for them to fashion theme elements, as well as a color printer for creative use.

Once the student's marble coasters have met all necessary requirements. They move on to constructing the side walls and roof. I prepare side supports by cutting cardboard strips, each measuring 1.5 inches by 9 inches. The students then hot glue these strips together to form an "L" shaped brace, which is attached to the corners of their cardboard marble coaster structure. The next step involves creating a hole in the top piece of cardboard, which I assist with. This hole must be strategically positioned directly above the top piece of the track within the coaster. After drilling the hole, the students attach this top piece to the side braces, effectively forming a cube-like enclosure for the marble coaster. The final and most critical step is testing the coaster. The students drop a marble through the top hole to ensure it lands correctly on the top track and continues its journey to the bottom. If the marble doesn't follow the intended path, students are encouraged to get creative, adding features or making adjustments to ensure the marble successfully completes its course. 

After students complete their marble coasters and meet all the project requirements, they can use Tinkercad to design a custom holder for the marble. This addition addresses a common issue where students take their coasters home and often lose the marbles, as there's no designated storage for them. Our solution involves leveraging Tinkercad and our Prusa 3D printer.

The challenge for the students is to design a marble holder that complements the theme of their coaster and ensures safe storage of the marble when the coaster is not in use. To assist with this, I've included the specific requirements for the marble holder with this message.

The design process begins with students using calipers to measure the marble size. They then create a preliminary model in Tinkercad before moving on to designing their custom holder. A key constraint is that the holder must not exceed a volume of 2 inches x 2 inches x 2 inches. This size limitation not only facilitates quick printing but also allows students to iterate their designs efficiently if the first attempt is unsuccessful.

Students often show creativity in this task. Some modify existing designs from the Tinkercad Library to accommodate a marble, while others build entirely new designs from basic shapes. Once their design is ready, they complete an order form and place it in my bin for printing. As I see the students every other day, I usually manage to print their marble holders before our next class.

In the final step, students attach their custom holders to their marble coasters. It's important to note that they are instructed not to place the holders on top of the coasters. The reason for this will become clear in the next phase of the project.

Every class participates in a school-wide competition where they see which class can build the tallest stack of coasters. The key is in the stacking technique: the end of one student's coaster must align with the beginning of another's. Although each student designs and creates their own coaster, these individual pieces come together to form a single, collaborative structure representing their class. This structure competes against those from other classes. This friendly contest fosters excellent communication and teamwork, as students work together to construct the tallest and most successful collective coaster.