What specific human factor contributes uncertainty when reading the meniscus in a graduated cylinder?

Answer

Slight variations in eye level or judgment

The act of observation introduces uncertainty because human factors, such as slight variations in eye level when reading curved surfaces or inconsistency in technique, create variability that cannot be eliminated merely by improving the equipment.

What specific human factor contributes uncertainty when reading the meniscus in a graduated cylinder?
measurementmethodexperimentuncertaintyerror