The document provides instructions for an experiment examining the rate of diffusion of acids and bases into water using Vernier probes. Students will test 5 samples of varying molarity and record the slope of the pH change over time. They are warned that the substances can burn skin and to handle probes gently. The molarity, or concentration in grams per liter, increases as the number of moles per liter increases. Higher molarity solutions diffuse faster, changing the pH more over time.