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4. Field Activity: Digital Fabrication for kids

For this activity, I used Adobe Illustrator and the laser cutter to make a human eye model for my 9-10s science class.

Human Eye Model Kit Human Eye Model Set Up

Background

I designed the human eye manipulative based on a model that I used to have students build as a part of our Light & Vision unit. Below is a photo of a previous version of the eye model.

Original Student-Built Eye Model Original Student-Built Eye Model

Students enjoyed working with the eye models, but the construction of the model took up too much time and wasn’t crucial to the learning objectives of the activity. I decided that the field activity was a great opportunity to design the manipulative for students. My goals for the model were to eliminate frustration that many students used to encounter and allow me to focus more instruction time on taking students through simulations to investigate the functions of different parts of the human eye more deeply.

Learning Outcomes

  • Students will understand the functions of the retina, lens, and vitreous chamber in the human eye.

  • Students will build a model to share how the parts of the eye work together.

  • Students will understand the relationship between the retina and brain.

The Design Process

Students will know how the different parts of the eye function together and separately.

Students will build a model to share how the parts of the eye work together.

Students will understand the relationship between the retina and brain.

I kept the design of the pieces as minimalistic as possible. My goal was to give each piece of the model a single function so that students could correlate each piece with a specific part of the eye. The parts of the eye represented by the model are the vitreous chamber, lens, and retina.

Human Eye Model Kit Human Eye Model Kit

I first designed a holder for the double convex lens that represents the inner lens of the eye. Students use two sizes during the lab, so I created two holders to work with both lens diameters. I also created two options for the semicircle edge of the holder to see which would hold the lens best. It ended up that .125 inches was the perfect width to hold both lenses securely, and I moved forward with that measurement for the rest of the kits. After laser cutting, the semicircles are glued to both sides of the center post of the holder. This creates a space for the lens to slip into.

Testing Out The Lens Holder Measurments Testing Out The Lens Holder Measurments

To represent the vitreous chamber and function as the structure of the eye model, I designed a base with a series of slots measured to fit the lens holder securely.

cutting out the base

To represent the retina, I designed a frame to hold a piece of paper. The paper catches the image that is projected through the lens. I added a slit for the base at the bottom of the frame to give the base a little height and added a second riser piece to for the base to slide into at the front to keep the base level to the table.

Students spent a lot of time choosing the perfect image.

Human Eye Model Kit

They measured the distance of the iPad from the lens before the image becomes blurry on the retina.

Human Eye Model Kit They explored how the image changes when adding different colored filters.

Human Eye Model Kit Recording Observations

Design Iterations

Design features that I would change after using the eye model with students:

  • Adjust the slots in the base to be slightly smaller to create a tighter fit for the lens holder to keep it upright.
  • Add a top arc to the lens holder to secure the lenses inside of the holder.
  • Add measurements to the notches in the base and note where to place the “retina.” -Shorten the 2 inch lens holder so that the lens is centered on the 1.67 inch lens.

Scopes Lesson Link

Lens Holder

Paper Holder + Riser

Base

Reflection:

How do you think digital fabrication improves the activity vs utilizing traditional methods? What is the extra value?

This is my third year using a variation of this teaching aid. In previous years, I have had students build the eye model using a lens and various materials. Some students enjoyed the challenge, while others found it frustrating. Digitally fabricating the model and printing enough for a half-class set allowed for everyone to enter the lesson on the same playing field. This year felt different in that each student was instantly engaged, and the kit was easy enough to use, so students were only challenged with using the lens to focus the image and later to run through the guided simulations. The digitally fabricated version allowed for more engagement with the content and freed up instruction time so that I could offer more check-ins with groups and more simulations for them to test.

Working in an emergent, project-based school requires a lot of curriculum development, and it can be difficult to find teaching aids that fully support learning goals. The ability to build a manipulative tailored to the content, is durable, and can be mass-produced quickly frees up prep time and gives me more time to think about differentiation and scaffolding.

What are some challenges you expect when you do the activity with your class?

I had anticipated that students would find it difficult to correlate the base with eye anatomy, but they quickly matched it to the vitreous chamber. This gave us a good jumping-off point to think about how the vitreous chamber, vitreous humor, and sclera work together to create a structure for the eye.

I also anticipated that the flipped image would surprise students, but some found it frustrating. Even after we discussed the brain’s role in correcting the image, some students found it distracting and spent much time flipping and locking the iPad image to produce a right-side-up projection. I’ll have to think about how to approach this best next year.

Structural issues I came across and will fix for next year were: Secure the lenses in the holders because they drop out easily Make the lens holder fit into the base more snuggly Add one more support between the paper holder and riser to stabilize the model

What have you learnt in the process? Describe the process that you went through to create the teaching aid. What did you learn during the fabrication process?

I first looked at iterations of the hand-built model students used in previous years. I chose which features were most accessible for students and which needed to be reworked. I kept the lens propped up on a holder, a piece of paper to catch the image, and a flat, slotted base design. Changes I made included adding more slots to the base, building a slot for the lens to rest within in the holder, a paper holder that would allow for easy threading of different types of paper during labs.

I drew my designs by hand first and calculated the measurements. I then built the pieces in Adobe Illustrator. Jaymes helped me speed up the process by sharing shortcuts, and in hindsight, it was unnecessary to do the work by hand first but I did find value in the process of drawing everything out. I added labels to the lens holders to indicate the lens size, changed my cut lines to the appropriate color and width, and then sent it to the laser be cut. I did learn that I need to make sure to create my designs in RGB to avoid having to convert it later.

After cutting one piece at the Franklin lab, I was able to test the model and make any final adjustments before cutting the rest of the set. I added a front riser at this point. At home, I am using a WeCreat which works a little differently. I was able to use the preview mode to place all of my pieces efficiently and added extra shapes and etchings in the unused space to test out etching settings and to avoid wasting materials. This was helpful because one full 12 inch by 12 inch sheet took an hour and forty minutes to cut and etch on a 40W diode laser. I just received a 20W diode laser for our school, and this experience will help me to plan my lessons accordingly for laser cutting onsite at school.