Biology / Unit 1 Bio 0155 short lesson, about 20 seconds
The pH Scale
Captions available
The idea
The pH scale measures how acidic or basic a solution is, based on hydrogen ion concentration, running 0 to 14 with 7 neutral.
In practice
Pure water sits at pH 7; a solution with more free hydrogen ions than pure water reads below 7.
Where people slip
Each whole step on the pH scale represents a tenfold change in hydrogen ion concentration, not a fixed, even step.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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