Building the FCC Crystal Structure with Playdough

Submitted by: Dr. Ipek Yucelen

Title: Modeling FCC Crystal Structure with Playdough Balls

Concept: Atomic Packing – Face-Centered Cubic (FCC)

Institution: University of South Florida

Course: Materials Engineering I

Level: Undergraduate | Also suitable for K-12 students

Semester: Summer 2025

Type: In-Class Demonstration / Hands-On Activity

Materials Needed: Playdough or modeling clay (2–3 colors), optional toothpicks or skewers

Description:

To help students understand atomic packing in crystal structures, students use playdough balls to physically build close-packed arrangements—such as face-centered cubic (FCC) structure.

They form spheres from playdough and stack them in layers, observing how the second layer fits into the grooves of the first. By continuing with a third layer, students can compare the stacking sequence (ABC for FCC). Color-coded layers make the differences easier to visualize.

To stabilize the models, toothpicks or small dowels can be used to gently hold the layers together.

Teaching Tips:

• Use different colors for each layer to help students visualize the ABC stacking sequence.

• Ask students to describe how the spheres nest into the grooves of the layer below.

• Follow up with a visual or short discussion on coordination number and packing efficiency in FCC structures.

3D Printed Crystal Structures

Submitted by: Dr. Ipek Yucelen

Title: 3D Printed Crystal Structures

Concept: Atomic Packing 

Institution: University of South Florida

Course: Materials Engineering I

Level: Undergraduate | Also suitable for K–12 outreach

Semester: Summer 2024

Type: 3D Printable Model / Visual Aid

Description:

Students can design and 3D print models of body-centered cubic (BCC) and face-centered cubic (FCC) unit cells to support in-class learning and K–12 outreach. These hands-on models help learners visualize atom positions, distinguish between different lattice types, and better understand concepts like coordination number and packing efficiency.

Teaching Tips:

• Use different colors or labeling to highlight center and face atoms.

• Compare atom count and packing efficiency between BCC and FCC using the models.

• Include these models in outreach kits for K–12 students to explore and assemble.