Light & Electron Microscopes

• They use light and a system of lenses to magnify images of small samples .

Advantages

• Image is shown in colour
• Cheaper than electron microscopes
• Smaller, easier to use
• The samples is alive

Disadvantages

• Lower reolution than electron microscopes
• An additional lamp is needed

• Use elrctrons instead of light to form an image.

Advantages:

• Clearer resolution-more detail
• No additional lamp is needed
• Greater depth of field

Disadvantaes:

• Mor expensive than light microscopes
• Big, so harder to use

• Scan a beam of electrons across the specimen
• Knocks off electrons from specimen, which are gathered in a cathode ray tube, which forms an image.

Advantages

• Can be used on thick specimens
• Produces a 3D image

Disadvantage

• Expensive
• Large
• Must be kept in an area with minimal electricm magnetic or vibration interference
• Lower resolution than TEMs

• Uses electromagnets to focus beams of electrons, dense areas of specimen absorb more electrons

Advantages

• Higher Resolution than SEMs
• Small objects can be seen clear
• Wavelength of electrons shorter
• Powerful magnification- greater detail

Disadvantages

• Can only be used on thin specimens
• All water has to be removed in a vaccum, so the cell must be dead
• Black & white image produced
• Potential artifacts from extensive sample preparation