Ping Pong Ball Lipid Bilayer

This model demonstrates the fluid mosaic structure of the cell membrane using ping-pong balls, drinking straws, water, oil, and salt water. The arrangement represents a phospholipid bilayer with hydrophilic heads and hydrophobic tails, showing how the membrane behaves in an aqueous environment.

1. See the links section below for full instructions.

📄 Making of a “Fluid Mosaic Model” - hkedcity.net: https://cd1.edb.hkedcity.net/cd/science/biology/resources/l&t2/model_making/model_making_E_1.pdf

• Add beads or small objects to represent proteins embedded in the membrane.
• Use food coloring in the water phase to emphasize separation.
• Show facilitated diffusion by using magnets to move objects across the “membrane.”
• Compare the model to diagrams of real cell membranes for discussion.

• Use caution when drilling holes in ping-pong balls.
• Handle hot glue carefully to avoid burns.
• Ensure oil and water are disposed of properly, not poured down the sink in large quantities.

• How does this model represent the phospholipid bilayer? (Hydrophilic heads interact with water, while hydrophobic tails avoid it and remain in the oil layer.)
• Why are the tails considered hydrophobic and the heads hydrophilic? (Due to their chemical polarity.)
• How does this model demonstrate the “fluid” aspect of the membrane? (The components are not rigid but can move within the layer.)
• How could proteins or channels be added to improve the accuracy of the model?
• What are the limitations of this model compared to a real cell membrane?