rm_27
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Are we meant to know the advantages and disadvantages of the light and electron microscope? If so, would this be sufficient:

Advantages of electron microscopes:

1)Higher magnification (TEM being x500 000 and SEM being x100 000, whereas light is only x1500)
2)Better resolution ( TEM = 0.1nm SEM= 5nm whereas light = 200nm)
3) SEM produces 3D images, thus able to see specimens in greater detail

Disadvantages of electron microscopes:

1) Vacuum needed as electron beams are deflected by air molecules (can someone explain this?)
2)Preparing sample and using microscope requires a high degree of skill and training
3) Costly

Advantages of light microscopes:

1) Cheaper and negligible running cost
2)Easier to use
3)??

Disadvantages of light microscopes:
1) Low magnification
2) Poor resolution, thus specimens cannot be seen in great detail
3) ??
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beyknowles
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(Original post by rm_27)
Are we meant to know the advantages and disadvantages of the light and electron microscope? If so, would this be sufficient:

Advantages of electron microscopes:

1)Higher magnification (TEM being x500 000 and SEM being x100 000, whereas light is only x1500)
2)Better resolution ( TEM = 0.1nm SEM= 5nm whereas light = 200nm)
3) SEM produces 3D images, thus able to see specimens in greater detail

Disadvantages of electron microscopes:

1) Vacuum needed as electron beams are deflected by air molecules (can someone explain this?)
2)Preparing sample and using microscope requires a high degree of skill and training
3) Costly

Advantages of light microscopes:

1) Cheaper and negligible running cost
2)Easier to use
3)??

Disadvantages of light microscopes:
1) Low magnification
2) Poor resolution, thus specimens cannot be seen in great detail
3) ??
If you look at the spec it'll tell you
I think this is it?: http://www.ocr.org.uk/Images/81028-specification.pdf

anyway,
  • bare in mind that with SEM's as well as producing a 3D image you can also also see surface structures
  • a vacuum is needed for electron microscopy, which means all the air is sucked out of the container/machine, because if not the air molecules would bounce against the electron molecules and they would be deflected, showing an unclear image.
  • you most certainly cannot 'see specimens in greater detail' using a scanning electron microscope. You can just see the 3D structure and surface structures. With a light microscope you can see internal structures and with a transmission electron microscope you can see the ultrastructure which esentially means in more detail. You can remember this because if you imagine scanning a product at a shop you scan the outside of the object and transmission is to pass through.
  • 'Preparing sample and using microscope requires a high degree of skill and training' might be good to mention why. Electron beams are so small in wavelength that you have to cut the tiniest slice of a specimen that you would use in to view through a light microscope
  • light microscope is more convenient
  • bare in mind the resolution and magnification of the light microscope is 'poor' in comparison to the electron microscope, I wouldn't say it is 'poor' in general


That's all I can think of as I only learn about microscope last month being as I've just started AS and I haven't thought about it since I left that lesson, hope it helped.

Edit: Realised my grammar isn't the best in this post because I'm tired sorry !!
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