Engineering Architectural Models: a Cumulative PBL Engineering Activity

As an elective engineering teacher (for Jonathan Alder High School in Plain City, Ohio) who teaches a range of high-school grade levels all together in one class, the end of the school year can be challenging logistically. State and end-of-course tests make it challenging to introduce new material to students without interruptions since different students are pulled out of class on different days for these tests during the last quarter of the school year. This is the perfect opportunity for me to have students reinforce and apply the concepts and tools they have learned throughout the first three quarters of the year (like the design process, measurement, technical sketching, 3D modeling, and electrical systems) through a student-led project-based learning activity.

In this project, students worked in small groups to make a scaled, architectural model of a building of their choice that includes an electrical circuit (also of their choice). The students began by developing their design through technical sketching and scaling before creating a 3D model of the building, modeling and developing an electrical plan, and finally constructing their functional model. The project shows students how all these tools and skills can work together in actual engineering practice.

The project is outlined in the subsequent steps both generally (at a lesson planning level) and with an example project that offers outcomes for each phase of the project you and/or students can use as a reference.

One perk of this project is that is shows students that they can turn what they consider garbage into something they can be proud of, which is a great lesson in sustainability. While the electrical components generally need to be supplied, students can upcycle materials for the majority of their projects.

Note: If your students are struggling to bring in materials, a quick email asking the custodial staff to save cardboard for your class will generally result in more cardboard than you can possibly imagine in only a couple of days.

The general materials needed for this project (though these may vary by building) are:

• Computer with internet access (for Tinkercad)
• Paper/pencil/ruler
• Cardboard
• Hot glue and/or tape
• Electrical components (coin cell battery, wire, resistors, LEDs, etc.)

In project based learning, it's critical for students to take time to clearly understand the project and - when possible - be a part of defining the requirements and constraints for that project.

The general project statement for this activity is as follows:

Create a scaled model of a building of your choice that includes an electrical system.

From this general project definition, students must work to define their own project requirements and constraints, including what building they will choose, what size/scaling they will use, what their electrical system will be, and what materials they will use.

The project definition for the example project that will be used in this Instructable is as follows:

Create a ~1:100 scale model of Young's Farm out of cardboard that includes functional storefront lighting.

As part of defining the project, students will need to select a building to create a scaled model of. For my project, I ask students to stay within the state of Ohio so that it is constrained a bit (otherwise they have a hard time narrowing down their selection) and also so that when all the groups have completed their projects, we can group them together to collaboratively represent what their most favorite elements of our state are.

For the example project, a student selected the main farm building for Young's Farm. Young's Jersey Dairy is a local landmark in that many students take school trips there to experience "farm life," get scrumptious ice cream, attend fall festivals, etc., and is a nostalgic memory for many of the students in my class.

As research shows, incorporating choice in projects has been shown to increase both interest and engagement in projects, so giving students the opportunity to choose a building that they have a personal connection to is an important component of this project.

In order to create an appropriately scaled model of the building they select, students will have to apply engineering logic and critically consider how to (1) determine the dimensions of the building they are trying to replicate, and (2) determine an appropriate scale for their final product. No one scale will be appropriate for all buildings, as some students may select something enormous like a sports arena and others may pick something small like their church, etc. This ill-structured element of the project pushes students to critically think about their project on their own, as opposed to being given specific guidelines and constraints at a class level.

My recommendation for how to approach this scaling is to use the scale in Google Maps (satellite view) to get an estimate of the overall length and width of the building and to use a feature of the building that can be estimated (such as a door height) to generate an estimate the height of the building.

Once the overall building dimensions are estimated, students will need to determine how big they want to make their overall project and determine how to scale all the dimensions to meet that size. They should have some logic for the size they select, though there is no correct answer. For instance, in the example project, the student set her size based on the convenience of working on the project in the classroom at her desk.

A breakdown of how these dimensions were estimated and how the scale was developed for the example project are included in the pictures for this step.

To complete the project definition, students will need to outline/sketch/define the circuit they plan to use in their model and how they plan to physically put it in their creations. Students in my class were welcome to use a variety of circuit components (from some students who used motors to make components spin to others who employed lights), but were required to set up and test their circuits on their own using the simulation tool in TinkercadCircuits (linked below) before receiving any physical components to use. This requires students to test their circuit designs and problem-solve/troubleshoot their circuits before attempting to put the actual components in their models.

Note: Since many students opted to use LEDs as part of their electrical component, this was a great time to review series vs. parallel circuits and how the different wiring impacts the brightness of the LEDs.

For the example project, the student was planning to light the storefront and roof of the building using four LEDs, as shown in the Tinkercad circuit diagram below. Because we explored circuits earlier in the year by making plush light-up toys earlier in the year, we use e-textiles electrical components (pictured) for this project, but standard resistors/LEDs/coin cell batteries could also easily be used for this project.

Once the project has been clearly and specifically defined, the next step for students is to make a plan for how they will approach the project through a design proposal. The goal of this step is to have students put their ideas on paper in a clean and clear way, though the sketches do not need to be perfectly scaled (since students will develop a 3D model in the next step that will accurately capture the intended scaling).

The design proposal should contain, at a minimum, the three main orthographic projections of the building (front, top, and right side - all appropriately aligned), the key dimensions (length, width, and height), materials used, and information related to the electrical components for the model. It should clearly explain how they are meeting each element of the project they defined. I always tell my students that their design proposal is done if and when they could hand their design proposals to any other group in the room and have them build it successfully without questions.

The design proposal for the example project is shown here for reference.

I recommend having this stage be a check-point with the students. Groups should meet individually with the instructor to explain their project, scaling, materials, electrical systems, etc. to get feedback and approval to move on to the next step. Many of my students had mis-scaled their designs or not fully considered how their circuitry would work, and it's best to catch those issues before students get into the modeling and construction phases of the project.

Once the design proposal is complete and has been reviewed by the instructor, the next step is for students to create a scaled, dimensioned 3D model of their building (again using Tinkercad, but this time using the 3D Design function). This step ensures that the calculations they have performed are correct and that the building looks the way they expect at these scaled dimensions before they start cutting into their materials. It also forces them to consider other dimensions they may not have captured in their initial scaling (such as where windows and doors go) in a specific, numerical way they can use and reference as they build their physical model.

This step offers a great way to allow team members with a strong interest in 3D modeling to get really detailed with their models and have some fun. Conversely, for students who may take a bit more time modeling, this step can be simplified to primarily ensure their key dimensions are accurate. The example model shown reflects the work of a student somewhere in the middle of that range.

Finally, students should use the dimensions from their 3D model to construct their scaled model. For many students, this hands-on portion of the project is their favorite, but also more challenging than they anticipate.

Make sure to begin this process with clear safety explanations for how to use any cardboard cutting knives, box-cutters, etc., you will use, hot glue guns, etc. This is also a great time to explain general craftsmanship expectations with students.

Additional Engineering Opportunities:

There are often features of students' buildings that offer additional engineering opportunities for them to explore. For example, a group that made a model of a McDonald's used syringes and tubing to make a pneumatically controlled drive-through window. Another group that made a race track was able to wire up and code a starting light (red to green) that really amped up their final model.

For the example project, I introduced the students to Thingiverse to show them opportunities to download and print pre-made 3D models (like the cow attached to the silo portion of the building) for a little extra fun.

The assessment strategy I use for this project is two-part. The first part looks broadly at the skills required to successfully complete this project (both technically and through their collaborative work), and confirms students' competency in each of the following areas:

• Measurement and Scaling
• Technical Sketching
• 3D modeling
• Electrical Systems
• General quality and Craftsmanship of the Final Design
• Problem-Solving and Critical Thinking
• Collaboration

The second portion of the assessment is a written reflection from the students. I cannot stress enough how much I value the element of reflection in assessing student work. It not only helps students try to put their knowledge on paper, but it reinforces technical writing skills and allows you to get a true sense of their experiences (both good and bad) with the project. Also, it helps students personally identify areas of strength and weakness as they move forward in their coursework.

The prompts for the reflection I asked students to complete aligned with the categories above and asked students to write a paragraph in each area, discussing things such as "Explain how you used measurement and scaling as you worked through this project."

To wrap up the project, I like to have students put all their projects together to capture the essence of what Ohio is in their eyes. This final compilation of all the projects pushes students to do their best work (since it will be part of a larger group project) and helps to develop a larger sense of community and collaboration.

I introduced this project during Covid when schools went remote and had students complete this work from home, but the project was so well-loved that I incorporate it each year now, back in the classroom. That said, this project would work for both remote and in-person instruction.

Here are some of the quotes from students about this project (captured from their reflections at the end of the project):

• "My overall thoughts on this project were that I liked it. I loved the fact that we got to choose a landmark that means something to us but also add in the elements of engineering we had learned throughout the year. I think this project was valuable in engineering ways as well as other mental ways. I personally had a lot of fun making this.
• "I genuinely enjoyed this project, I love to build and do hands-on things. I put a lot of effort into this project and I'm proud of the final result. This was probably my favorite project of the school year and I think others enjoyed it too. I liked how it wasn't overwhelmingly hard, but that we all seemed to have some sort of challenge(s) we had to overcome."

I hope your students enjoy this project as well.