pH meter, 1950-1970.
4 0 c m
actual image size: 26cm x 32cm

pH meter, 1950-1970.

Exton, David

© Science Museum / Science & Society Picture Library


Direct reading pH meter, model 23A, made by Electronic Instruments Ltd of Richmond, Surrey, UK. In chemistry the pH value of something (for example rainfall) refers to its acidity or alkalinity, whereby a pH value of 7 is neutral, values lower than 7 are more acid and higher than 7 more alkaline.



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