Ectoplasm: Colloidal Fog in a Bottle

This simulation recreates a classic chemistry demonstration behind a spooky name: dissolve a resin like mastic or rosin in alcohol, then pour that tincture into water. The resin won't dissolve in water, so it instantly precipitates into a cloud of countless microscopic droplets — colloidal particles roughly a micron or less across, far too small to see individually but large enough to scatter light. Pour the mixture, drag the flashlight to aim its beam through the jar, and watch the Tyndall effect appear: a glowing scattering cone wherever the beam crosses dense-enough colloid, and an invisible or faint beam wherever it doesn't. The particle size slider is the real physics knob — too small and the particles behave like a true solution with no visible scattering, too large and they sink out of suspension as sediment instead of staying dispersed, and only the colloidal size range in between produces the classic glowing "ectoplasm" beam.