A survey of 21 free online buffer calculators and apps found only 2 that correctly calculated pH under conditions where [H[superscript +]] and [OH[superscript -]] cannot be ignored in the ratio term of the Henderson-Hasselbalch equation. Traditional guidelines for when use of formal concentrations is acceptable were found to be flawed. For acidic…

As I approach my 70th year in physics, let me tell my younger colleagues about my adventures with computation. When I was 14, my father gave me a slide rule because I appeared to be headed toward a career in physics. Since then, I have had experience with many other calculating devices.