pH measurement quantifies hydrogen-ion concentration as pH = −log₁₀[H⁺] on a 0–14 scale, sensed via a glass-electrode measuring half-cell paired with a reference half-cell whose potential difference is proportional to hydrogen-ion concentration, requiring temperature compensation and an extremely high-input-impedance amplifier to avoid loading the glass electrode's high source impedance. Viscosity measurement quantifies a fluid's resistance to shear via absolute (dynamic) viscosity, defined through Newton's law of viscosity (shear stress proportional to velocity gradient) and kinematic viscosity (absolute viscosity over density), determined industrially via rotating-concentric-cylinder (torque-based) and capillary-flow (pressure-drop-based) methods. Both belong to analytical instrumentation, applying electrochemical and fluid-mechanical theory to process/quality monitoring.
pH measurement quantifies hydrogen-ion concentration as pH = −log₁₀[H⁺] on a 0–14 scale, sensed via a glass-electrode measuring half-cell paired with a reference half-cell whose potential difference …