Microscopes • Micro= Scope= • Small -to view A microscope is an instrument used to view very small objects. In biology it is used to view living…. cells and unicellular organisms.
Compound Light Microscope Eyepiece / Ocular lens X10 Nose Arm Revolving lenses Stage and Stage clips Course Adjustment knob: Moves stage up and down Fine adjustment knob: Fine focuses the image for your eyes
High power objective Medium power objective lens Low power objective lens. Longest in length Blue in color x40 Shortest lens Red in color X4 Medium in length Yellow in color X 10
Diaphragm: regulates the amount of light that passes through the stage Light source Base
There are 3 types of microscopes are used in biology: 1. Compound light microscope -Compound- look through 2 lenses at the same time in order to properly magnify the organism.
Total magnification: low power: ocular lens x10 low objective x4 -------------- x40 medium power: ocular lens x10 med objective x10 -------------- x100 high power: ocular lens x10 high objective x40 -------------- x400
Compound light microscope: -light -light must pass through the diaphragm and through the object. -object must be “thin” or transparent so the light can pass through it.
Staining Is a method of adding color to a cell so that the cell and its structures can be seen more clearly through a microscope.
Limit of Resolution The limit of resolution is the point at which you see an item most clearly. Any magnification above or below that point will results in the object looking blurry.
Type 2: Stereoscope -Used to view the surface of objects which are too large for light to pass through them. -Uses to lights to illuminate the surface of the object. -Stereo means “3 dimensional” -Provides a 3-D detailed look at the surface of an object.
-look through • 2 ocular lenses • -magnifies between x10 to x60
Type 3: Electron Microscopes Uses electrons to form an image and NOT light Has a very high limit of resolution. -can see items very clearly at any magnification -can magnify up to 500,000x and still be clear • Object is placed in a vacuum • No air • No oxygen • Organism is DEAD
Two types of electron microscopes: 1. T.E.M. ~ Transmission Electron Microscope • Produces a 2-D, black and white image of inside of a cell.
Produces a 3-D, black and white image of the surface of an object. 2. S.E.M. ~ Scanning Electron Microscope
Additional tools of a biologist: Tool used to separate the components of a mixture by their different densities. • Chromatography: