Microscopes are used to increase the magnification and
resolving power of the unaided eye MICROSCOPES
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MAGNIFICATION: the ability of the lens to enlarge the image
Total Magnification = Magnification of Objective lens x
Magnification of ocular lens RESOLVING POWER: the ability to
deliver a clear, sharp image by distinguishing between two objects
that are close together DEFINITIONS
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1.SIMPLE LIGHT MICROSCOPE A single lens and light source TYPES
OF MICROSCOPES
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2. COMPOUND LIGHT MICROSCOPE Two lenses (objective and ocular
lens) and a light source TYPES OF MICROSCOPES
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3. TRANSMISSION ELECTRON MICROSCOPE (TEM) A beam of electrons
is transmitted through a very thin specimen An image is formed from
the interaction of the electrons transmitted The cells must be dead
in order to view Image can be magnified up to 5 000 000 x
Resolution up to 2 nm TYPES OF MICROSCOPES
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TEM
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4. SCANNING ELECTRON MICROSCOPE (SEM) A sample is imaged by
scanning it with a beam of electrons The electrons interact with
the atoms and produce signals that will create a 3D image The
specimen can be thick The image can be magnified up to 300 000 x
Resolution up to 10 nm TYPES OF MICROSCOPES
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SEM
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Slide 12
Complete the following chart by placing a checkmark in the
correct boxes COMPARING TEM AND SEM TEMSEM Specimen must be very
thin Specimen must be dead Electrons pass through specimen
Electrons scan specimen Higher magnification Higher resolution
Slide 13
Complete the following chart by placing a checkmark in the
correct boxes COMPARING TEM AND SEM TEMSEM Specimen must be very
thin * Specimen must be dead * Electrons pass through specimen *
Electrons scan specimen * Higher magnification * Higher resolution
* Produces a 3D image *
