Week 6: Colloids and Emulsions

Why a simmered broth turns milky and stays that way — Stokes' law, droplet size, and closing Stage 2's run of network-and-dispersion structures.

29 March 2027

Outline#

• Recap: Modules 4–5 built resistance to flow through a true network — crystallite bridges, then percolating protein aggregates. This lecture’s structure resists flow without ever forming one.
• Deriving Stokes’ law for creaming velocity, then asking which variable a cook can actually change: droplet size dominates over the density difference, because it enters the law squared.
• Why a long-simmered bone broth stays milky: droplet size set during simmering, not a change in the oil-water density gap, is what is doing the stabilising.
• Naming where Stokes’ law breaks down for a real broth — a reminder that every model on this site states its own limits, not just its result.
• Closing Stage 2: Modules 4–6 gave three different structural answers (crystallite network, protein network, stabilised dispersion) to one question — what makes a food resist flow. Stage 3 asks how cooking changes each of these structures, starting with Module 7’s transport.