types of microscope electron microscope an electron microscope
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Types of microscope
An electron microscope
Magnification = The number of times the image has been enlarged by the microscope, bigger than the objects real actual size. LM max mag. = 1,500X, EM max mag. 500,000X
Resolution (or Resolving power) =The ability of the microscope to distinguish clearly between 2 points that are extremely close together.
Figure 1.1 Magnification vs. Resolution
ResolutionThe Light Microscope has a resolving power of around 250nm (nanometers) which is the same as 0.25m (micrometers), so if two objects are closer than 0.25m they will not be detected as 2 clear points.The Electron Microscope has much better resolving power of around 1nm, which is the same as 0.001m, so it can detect much greater detail.
See my pdf notes comparing wavelenths of light and an electron beam
There are 2 different types of Electron Microscope:
Transmission electron microscope
A transmission electron microscope produces 2D images from electrons which pass through the sample. An extremely thin specimen is needed.
Golgi body surrounded by mitochondria in a mouse myeloid cell
A plant cell
Scanning Electron Microscope
A scanning electron microscope produces 3D images from electrons reflected off the samples surface.
Isolated mitochondria from bovine lymphocytes
Philonicus albiceps head
This cell is a type of skin cancer cell. The cell has been frozen and split open to reveal its nucleus (central red area). (Image: Anne Weston)
What next?Complete the comparison tables on the bottom of your Handbook p4 and the top of p5 booklet by circling the correct choices and crossing out the wrong ones - use textbook pages 43-45 to help.
Now complete tasks found in the middle of handbook p5.
Units of measurement1m (1 metre) = 1000mm1mm = 1000m (micrometres)1 m = 1000 nm (nanometres)To convert mm to m multiply by 1000To convert m to mm divide by 1000When doing calculations you need to make sure that your measurements are in the same units.