Counting chambers are instruments for precise measuring. They are made of special optical glass and serve to
determine the number of particles in liquids. Nowadays the Neubauer-improved counting chambers has become the most
popular one.
Its standard depth is 0.1 mm. The grid consists of 3 x 3 large squares with
areas of 1 mm² each. The large square in the center is subdivided into
5 x 5 group squares with edges of each 0.2 mm length and areas of
0.04 mm². These group squares are again subdivided into sixteen small
squares of an area of each 0.05 mm x 0.05 mm = 0.0025 mm².
