Growth rates of the nuclei appear to vary wildly throughout the sulfur sol formation, but the assumptions for the COP model still appear satisfied. After the nucleation phase, G is approximately 0.12 ± 0.02 million S 8 units per minute, as estimated from Zaiser and LaMer's particle size data (see S5). This value is about three orders of magnitude smaller than the predicted growth rate during the nucleation burst, which might be explained by the reduced level of supersaturation after nucleation compared with the maximum (estimated at C m /C s ≈ 20-40). Using the difference, I approximate a value of G ′ m and predict that |Q ′ m -G ′ m p m | is around 2-3 orders of magnitude smaller than G m J m (see S6), suggesting the first assumption of the COP model is valid for this system. Furthermore, the duration of the nucleation period can be estimated with the COP model, yielding values of 0.2-0.5 s (see S6) and supporting the second assumption of the COP model in that these are much smaller than the other timescales of the process, which are on the order of minutes to hours. This illustrates that the COP model should be widely applicable to LaMer burst systems, even where Q and G are not constants throughout the process.