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 Compound Light  Visible light is used to illuminate the specimen  Glass lens bend the light to magnify the image  Magnifies up to 1,000X  Limited resolution  Able to view living things  Various techniques can be used to differentiate structures – dyes, fluorescence

 Electron  Beam of electrons to view image  Much greater magnification  Better resolution  Cannot view living things  Transmission Electron Microscope (TEM)  Shows internal detail  Scanning Electron Microscope (SEM)  Gives 3-dimensional image of surface Scanning ↑ Transmission ↓

10 m 1 m 0.1 m 1 cm 1 mm 100 µm 10 µm 1 µm 100 nm 10 nm 1 nm 0.1 nm Atoms Small molecules Lipids Proteins Ribosomes Viruses Smallest bacteria Mitochondrion Nucleus Most bacteria Most plant and animal cells Frog egg Chicken egg Length of some nerve and muscle cells Human height Unaided eye Light microscope Electron microscope

 Eye piece or ocular lens  What you look thru  Magnifies 10X  Revolving nosepiece  Allow you to change the objective lens  Objective lenses  Magnify the image  Scanning Power 4X  Low Power 10X  High Power 40X  Stage  Holds the slide  Mechanical stage makes adjustments easy

 Light Source  Illuminates the object  Diaphragm  Adjustable lever below stage  Regulates the amount of light passing through the image (too bright – close / too dark – open)  Base  Supports the microscope  What you hold to carry it  Coarse adjustment  Focus in large increments  Only use with scanning & low  Fine adjustment  Focus in small increments

 Start on the scanning objective  Use the coarse adjustment to bring object into view  Use fine adjustment to make clear  Move object to center of field of view  Switch objectives use fine adjustment to make clear  NEVER use coarse adjustment on high power

 Place a drop of water onto slide  Place object in water  Use a probe to slowly lower the cover slip onto the slide  Try to avoid air bubbles

 Total magnification = magnification of the ocular lens X the magnification of the objective lens  Scanning Power Total Magnification:  10 X 4 = 40  Low Power Total Magnification:  10 X 10 = 100  High Power Total Magnification:  10 X 40 = 400

 Draw to the best of your ability  No scribbling  No lines/dot  Label the image  What are you looking at?  Document the total magnification that you are using at the time.  40X, 100X or 400X