Compare simple cubic, body-centered cubic and face-centered cubic unit cells. Inspect shared sites, change lattice spacing, and watch exaggerated thermal vibrations around equilibrium positions.
• 3D scene parts: eight shared corner sites; body / face sites; unit-cell boundaries; highlighted (100) plane; site accounting and scale. • Controls: cubic structure (Simple cubic, Body-centered cubic, Face-centered cubic), lattice parameter a (0.25–0.6 nm), temperature (0–900 K), atom display size (0.2–1 fraction of touching radius). • Live readouts: effective atoms per cell; coordination number; hard-sphere packing fraction; touching atomic radius; sites per cell volume; illustrative vibration amplitude. • Guided experiments: Compare close packing; Stop thermal motion; Expand cell spacing. • Four tabs (visual laboratory, curves and measurements, experiments, learn and assess), a model-verification run, a timestamped event log and a trial report.
SC: n=1, CN=6, r=a/2, APF=π/6 BCC: n=2, CN=8, r=√3 a/4, APF=√3 π/8 FCC: n=4, CN=12, r=√2 a/4, APF=π/(3√2) Site density=n/a³. Vibration amplitude=0.02a√(T/300).
Hard-sphere cubic geometry with independent, visibly slowed harmonic site motion. Temperature controls illustrative vibration amplitude only; this is not molecular dynamics, phonon dispersion, thermal expansion, or a real-material density model. Display-size slider does not alter calculated packing. Try the preset experiments, then compare the live readouts with the equations.
No, their combined contribution is one. Each corner belongs to eight adjacent cells.
No. The display scale is separate from the touching-sphere geometry.
Hard-sphere cubic geometry with independent, visibly slowed harmonic site motion. Temperature controls illustrative vibration amplitude only; this is not molecular dynamics, phonon dispersion, thermal expansion, or a real-material density model. Display-size slider does not alter calculated packing.