Transitions lenses contain special patented photochromic dyes that cause the lens to activate, or darken, when exposed to ultraviolet rays from sunlight. When the UV light diminishes, the lenses fade back. As light conditions change, the level of tint adjusts, offering the right tint at the right time.
Pure water is not a good conductor of electricity. Ordinary distilled water in equilibrium with carbon dioxide of the air has a conductivity of about 10 x 10-6 W-1*m-1 (20 dS/m). Because the electrical current is transported by the ions in solution, the conductivity increases as the concentration of ions increases.