Chemical and biological theories come to life in this natural continuation to the study of Osmosis and Diffusion (LAB-22)
. In this activity, students use a colloidal solution of starch and sodium chloride to vividly observe dialysis. They also observe diffusion of a solute through a semi-permeable membrane. Students then remove an inorganic salt from a colloid and test for the presence of chloride ions and starch with simple color tests. Individualized worksheets guide students through the step-by-step procedure in this self-directed lab activity.