Giant Ionic Lattice Simulation — Description
The simulation shows a 5×4×4 NaCl lattice of 80 ions rendered in 3D using Three.js. Na⁺ ions appear purple and smaller, Cl⁻ ions appear green and larger, reflecting their real relative ionic radii. Yellow lines represent the electrostatic attraction between each Na⁺ and its six adjacent Cl⁻ neighbours. Students can orbit, zoom, and hover over individual ions to read tooltip explanations. Four toggleable controls explore the four key properties of ionic compounds required by AQA GCSE Chemistry:
⚡ Voltage — in solid state the ions stay fixed and a “no current” badge appears. Combine with Melt or Dissolve and ions migrate directionally: Na⁺ toward the cathode, Cl⁻ toward the anode, modelling electrolysis with electrode products named.
🔨 Apply Force — the upper lattice layers shift along the slip plane. Once like charges align the bond lines turn red and a repulsion badge fires, explaining why ionic lattices shatter rather than deform.
🌡 Melt — ions break from fixed positions into continuous thermal random walk, with heat glow. Applying voltage now drives directed ion migration.
💧 Dissolve — ions spread radially outward (water separating them from the lattice), then immediately begin free random thermal motion in solution — correcting the common misconception that dissolved ions are stationary. Applying voltage drives electrolysis migration on top of the thermal movement.
The Labels panel gives context-aware AQA teach text for every state combination. Full SEND accessibility modal included.
Suggested Class Activity
“Four Properties Challenge” — Predict, Observe, Explain
Suits a 20–30 min segment within a lesson on structure and bonding, Year 10/11.
Setup: Display the simulation on the board. Students work in pairs with a printed or digital observation sheet (three columns: Predict → Observe → Explain).
Round 1 — Voltage (solid) Pose the question: “NaCl is made of charged particles. So why doesn’t solid NaCl conduct electricity?” Students write a prediction, then you toggle Voltage. They observe the no-current badge and fixed ions, then write an explanation using the words ions, fixed, lattice, mobile.
Round 2 — Force Ask: “What do you think will happen if we hammer this crystal?” After predictions, toggle Apply Force slowly. Students observe the layer shift, the bond lines turning red, and the repulsion badge. Key writing task: explain in two sentences why ionic compounds are brittle but metals are not — the contrast with the metallic bonding simulation makes this land well if shown side by side.
Round 3 — Melt then Voltage Turn off Force. Ask: “If we melt NaCl and then connect it to a battery, what happens now — and why is that different from the solid?” Toggle Melt, pause, then add Voltage. Students observe directed ion drift and the conduction badge. Discuss: what are the products at each electrode?
Round 4 — Dissolve then Voltage Reset. Ask: “Does dissolving in water have the same effect as melting?” Toggle Dissolve. Students observe the spreading and then the continuous random motion. Add Voltage — same directed drift. Discussion question: why do the ions keep moving even when there’s no voltage applied? This directly addresses the misconception the simulation was built to fix.
Plenary question (exit ticket): “A student says: dissolved NaCl ions just sit still in the water. Use the simulation to explain why they are wrong.”
The simulation pairs naturally with the metallic bonding one for a compare-and-contrast double lesson on structure and bonding — brittle vs malleable, no free electrons vs delocalised sea, fixed ions vs sliding layers.