This is a hemocytometer.

By Todd - originally posted to Flickr as 0356, CC BY-SA 2.0, Link

How does a hemocytometer measure volume?

Using a hemocytometer is an inexpensive and accurate method to determine the concentration of living cells in a culture. A hemocytometer is a type of microscope slide that has a very precise grid etched into its surface. The grid is divided into several primary squares that have a 1 mm by 1 mm dimension and the grid is separated from the coverslip by 0.1 mm. Using these dimensions allows you to calculate the volume using the following equation: length * width * depth = volume. Therefore, each counted primary represents the number of cells found in 0.1 ml of volume.

Learning Objectives:

- 1.4 - Count cells using a hemocytometer.