Re: How can you tell that a cell has depth or thickness?

  When you observe a cell under a microscope, especially at higher 
magnification, the fact that you have to focus up and down through the cell 
to see different parts of it is an indicator that the cell has a certain 
thickness.  On some microscopes, the fine focus is calibrated in microns 
(millionths of a meter) so you can actually measure the approximate 
thickness of a cell by how far you turn the fine focus knob to focus from 
one side of the cell to the other.  In general, cells are about 10 to 20 
microns in thickness but this can vary quite a bit depending on the cell 
type and how it was prepared.  Some more sophistacated microscopes like 
Laser Scanning Confocal Microscope or a Scanning Electron Microscope allow 
you to take more accurate measurements of cell thickness but a simple 
student microscope can give you a pretty good estimate.