Introduction: Niffler Containment Box

About: I'm a farmer, teacher and tinkerer.

Math is fun! Sometimes it doesn't feel that way to students though. In order to make the practice of fractions, decimals, and measurements more engaging, we ask students to design and 3D print a box to contain their pet Niffler (a Harry Potter character). Our advanced 6th grade and 7th grade algebra classes do this project near the beginning of the year. They practice fraction to decimal conversions centimeter to inches conversions, measuring, thinking three dimensionally and identifying the relationship between good planning and successful implementation.

Here's the hook:

Congratulations, you just finished your first month at the Colorado Academy Witchery and Wizardry School. You are about to return home to your muggle parents, but your new friend Niffler wants to come along. The problem is that Niffler has very sticky fingers and will steal anything in front of him. To help you out, Ms. Kies has ordered a magical material that will help entrap Niffler in his box. The only problem, the material is not molded into a form and you need to help design the box for Niffler. Niffler is about an inch tall and half an inch around so he can squeeze through holes any bigger than that.

See the rubric and day by day breakdown on this document.

Colorado Standard Grade Level Expectation Seventh Grade:
Standard 1: Number Sense, Properties, and Operations

1. Proportional reasoning involves comparisons and multiplicative relationships among ratios

Standard 4: Shape, Dimension, and Geometric Relationships

1. Modeling geometric figures and relationships leads to informal spatial reasoning and proof

2. Linear measure, angle measure, area, and volume are fundamentally different and require different units of measure

21st Century Skills and Readiness Competencies in Mathematics

Critical Thinking and Reasoning: Mathematics is a discipline grounded in critical thinking and reasoning. Doing mathematics involves recognizing problematic aspects of situations, devising and carrying out strategies, evaluating the reasonableness of solutions, and justifying methods, strategies, and solutions. Mathematics provides the grammar and structure that make it possible to describe patterns that exist in nature and society.

Information Literacy: The discipline of mathematics equips students with tools and habits of mind to organize and interpret quantitative data. Informationally literate mathematics students effectively use learning tools, including technology, and clearly communicate using mathematical language.

Self-Direction: Doing mathematics requires a productive disposition and self-direction. It involves monitoring and assessing one’s mathematical thinking and persistence in searching for patterns, relationships, and sensible solutions.

Invention: Mathematics is a dynamic discipline, ever expanding as new ideas are contributed. Invention is the key element as students make and test conjectures, create mathematical models of real-world phenomena, generalize results, and make connections among ideas, strategies and solutions.

Niffler image by Lambidy.

See Colorado Math Standards Here


- Graph paper

- Pencils

- Rulers

- 3D printer and filament

- 3D modeling software (we use Solidworks)

Step 1: Design Your Box

I like to use Isometric dot paper to draw ideas in 3D, but when it comes to dimensioning, graph paper is better. Students should consider different box design options before choosing the best one. Some of them will choose the easiest idea, but many will challenge themselves to make a unique design. They will then draw the box on their graph paper, labeling all necessary dimensions to make it the correct size to contain Niffler.

See full example documentation.

Step 2: Create Your Box in Solidworks

For this kind of project, I prefer Solidworks, Fusion 360 or Inventor to Tinkercad. We want to emphasize defining the relationships between shapes and accurate dimensioning. I also really like that when students enter dimensions in fractions, the software automatically converts them to decimals. It's another reminder that they are two different expressions of the same information. It also often prompts conversations about rounding.

On the first day of modeling, I demonstrate creating and shelling the box. Then I show them how to draw on a surface in order to cut out their ventilation holes.

On the second day of modeling, I demonstrate how to edit features and sketches. Then I show them how to create a lid and upload their .stl files. Depending on our schedule, we will have a third day of modeling.

Full Solidworks Instructions

Step 3: Print Boxes

I collect students files in Google Drive folders shared with the students in each class. They upload the files to the folder and then fill out the print request form. I generally print batches of each color instead of printing them in the order they were submitted. I also scale them down by 50% or 75% to make them print faster. This adds more math! Students must measure their boxes and determine the scale I used before they submit the box to their math teacher. Later in the year, the boxes can be used in calculating surface area and volume!

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