Meniscus

Stand it upright on a level surface and read the bottom of the curved meniscus at eye level, using a unit such as cm³ or mL. A gas volume can be measured with a gas syringe attached to an apparatus that collects the gas; read the scale at the syringe piston and check that the connections do not leak.

Keep it upright and read the bottom of the meniscus at eye level, recording the volume in cm³ or mL. A gas volume can be measured with a gas syringe: connect it to the apparatus collecting the gas and read the piston position against its scale. To measure pH, dip pH paper into a sample and compare its colour with the supplied chart, or use a calibrated pH meter for a numerical reading. pH has no unit.