Microscopy

Definition:  Resolution

• The minimum distance between two objects where they can still be seen as two separate entities

OR

• The ability to distinguish two separate points
• The resolution is normally measured in nm (nanometers)

Definition: Magnification

The number of times the image size of an object is enlarged by

1 micrometer = 1000nm

1mm = 1000 micrometres  

Definition:  Resolution

Pros and cons of light microscopes:

Pros:

• Can be used on living cells 
• Can observe cell division due to them being living
• Inexpensive 
• Small and portable
• Simple sample prep

Cons:

• Staining can cause cell death
• Lower resolution (200nm)
• Lower magnification (x2000)

Electron Microscopy:

Pros:

• Over x5000,000 magnification
• Better resolution (SEM=3-10nm) and (TEM 0.5nm)

Cons:

• Cannot view living specimens
• Can lead to artefacts (false images) due to sample preparation
• Requires careful prep and staining