Mean relative kinetic energy in the NanoRocks tray 1 after a shaking event. The red curve shows the fit with the parameters T₀ = 2.70 × 10⁻¹⁰ J and τ₀ = 1.64 s. The computed mean coefficient of restitution for this shaking cycle is ɛ = 0.89. The inset shows the mean coefficient of restitution for each NanoRocks tray calculated using these fit parameters averaged over 178 shaking cycles (black asterisks, see Table 1 for a tray description). When possible, we also calculated the average coefficient of restitution using the same method based on the automated tracking data (green diamonds).