PROJECT PROPOSAL: THE INTERACTIVE BOHR ATOMIC MODEL

"The Interactive Bohr Atomic Model is a fully 3D-printable, snap-fit educational tool designed to bridge the gap between abstract quantum physics and tactile STEM learning. It allows students to physically 'build' elements, transforming textbook diagrams into a hands-on classroom experience."

## Innovative Design Features (100% 3D Printed)

• Zero-Hardware Assembly (Snap-Fit & Dovetail): The entire model—from the central nucleus hub to the concentric electron shells—interlocks seamlessly using smart plastic tolerances, snap-pins, and dovetail joints. No screws, no glue, and no external hardware are required, maximizing the efficiency and purity of 3D printing technology.
• Customizable & Reusable Element Card System: Instead of wasting filament to print separate cards for every single element, the model features a blank 3D-printed base card. Users simply write the element's name, atomic number, or electron configuration on a standard slip of paper and stick it onto the card (using tape or a sticky note). This paper-on-card assembly then slides into a dedicated dovetail slot on the model's base, making the system infinitely reusable for all 118 elements.
• Mechanical Kinetic Electron Tracks: Instead of static parts, the concentric rings representing the electron shells feature a custom-designed U-shaped captive track. Students drop standard 3D-printed marbles into these tracks to represent electrons. The marbles can spin and roll freely around the nucleus, simulating the continuous movement of electrons.

## Classroom Application & Interaction (The STEM Learning Flow)

1. Step 1: Write & Stick the Element: The student takes the blank 3D-printed Element Card. They write the details of their chosen element (for example: Oxygen, Atomic Number 8) onto a small piece of paper, stick the paper onto the card, and then slide the card into the base slot for clear reference.
2. Step 3: Construct the Nucleus: Based on the information on the card, the student snaps 8 Proton spheres and 8 Neutron spheres (printed in contrasting colors) into the central nucleus grid.
3. Step 3: Distribute the Electrons: The student drops 2 marble electrons into the innermost track (the first shell) and 6 marble electrons into the second track (the second shell).
4. Step 4: Engage and Observe: Students can flick the marbles to watch them orbit the nucleus. They can also manually move a marble from an inner track to an outer track to visualize electron excitation and energy levels.

## Engineering & 3D Printing Specifications

• The Captive Marble Track: The U-shaped track is engineered to wrap around the marble by roughly 60% to 65% of its diameter. This keeps the marbles securely trapped inside the track even if the board is tilted vertically, while still allowing them to roll smoothly with minimal friction.
• The Card Slot Joint: The base utilizes a dovetail joint for the element card holder. A tight tolerance of 0.15mm to 0.2mm creates enough friction to hold the paper-and-card assembly perfectly in place without needing a latch.
• Printability & Economy: All concentric rings and the base are designed to be printed completely flat on the print bed. This ensures maximum bed adhesion, eliminates the need for messy support materials, and makes post-processing entirely non-existent. It is highly optimized for standard classroom 3D printers.