MICROSCOPY
ELECTRON MICROSCOPY LIGHT MICROSCOPY
Purpose: to view images with a greater resolution than 200nm MAGNIFICATION – The number of times greater an image is than the
actual object
Benefits of using an electron beam:
Magnification = size of image / actual size of object
• Free electrons behave like electromagnetic radiation
• Wavelength is extremely short M=I/A
• Can be easily focused using electromagnets since they are
RESOLUTION – Ability to distinguish between two separate points that
negatively charged
are very close together
Resolution: 0.5 nm Greater the resolution, greater the clarity of the image
Scanning electron microscope Maximum resolution: 200 nm
• Beams of electrons scan the surface of the specimen
• Surface structure can be seen (3D image)
• Resolution: 3 nm – 20 nm
Transmission electron microscope
• Beam of electrons are passed through the specimen
• Can see inside cells
Disadvantages:
• Specimen and the fluorescent screen must be in a vacuum
• Only dead specimens can be examined
ELECTRON MICROSCOPY LIGHT MICROSCOPY
Purpose: to view images with a greater resolution than 200nm MAGNIFICATION – The number of times greater an image is than the
actual object
Benefits of using an electron beam:
Magnification = size of image / actual size of object
• Free electrons behave like electromagnetic radiation
• Wavelength is extremely short M=I/A
• Can be easily focused using electromagnets since they are
RESOLUTION – Ability to distinguish between two separate points that
negatively charged
are very close together
Resolution: 0.5 nm Greater the resolution, greater the clarity of the image
Scanning electron microscope Maximum resolution: 200 nm
• Beams of electrons scan the surface of the specimen
• Surface structure can be seen (3D image)
• Resolution: 3 nm – 20 nm
Transmission electron microscope
• Beam of electrons are passed through the specimen
• Can see inside cells
Disadvantages:
• Specimen and the fluorescent screen must be in a vacuum
• Only dead specimens can be examined
