Microscopy information Cells

Microscopes* Study objects too small to naked eye 2 types  Simple  one lense (magnifying glass) Compound two lenses 3 “systems”: optical, mechanical, light **Compound microscope = Most Common**

“Systems” of Compound Microscopes Optical 2 + objectives (each w/different magnifying power – low & high power) Mechanical Structural components (ex: base, arm, stage, nose piece) Light Mirror, diaphragm Do not need to write down

PARTS TO KNOW…* Ocular/eyepiece Objectives Revolving nosepiece *DEFINE & Stage, stage clips LABEL IN Coarse adjustment LAB PACKET Fine adjustment Light source Diaphragm Arm Body tube Base Do not need to write down; fill in lab packet

Magnification* Enlargement of the image created by the lenses Two sources  1. Ocular = eye piece (10x or less) 2. Objective lenses Shorter: low power, 10x mag. Longer: high power, 40x mag. Magnification overall  ocular x objective lenses 10 x 40 (varies) 400x’s greater than actual image

Resolution* Aka sharpness of an image Microscope spreads “details” of pictures apart – so human eye can make them out Shows two points close together separately Cannot increase magnification power if resolving power is not also increased

Field of Vision vs. Depth of Field* F.O.V D.O.F How much of the area of the slide you can see at one time magn., F.O.V Some parts focused, other parts not in focus – due to objects being 3-D in nature magn., D.O.F

Preparing a Microscope.. Hold arm & base “ocular” and “arm” towards you Clean “ocular” and “objective lenses” with lens paper Adjust “nose piece/objective lens” to lowest power (10x) Turn on light, adjust mirror, alter diaphragm if needed Look through with BOTH eyes open

Observing a Slide.. Place slide under stage clips Lower low-power objective to directly above, but NOT TOUCHING slide *do so with coarse adjustment knob – moves entire body tube Focus with coarse adjustment knob Focus with fine adjustment knob Add/decrease light if needed Adjust to medium power, then to high power *must focus at 10x before advancing!!*

How to make a Wet Mount.. Obtain clean side & coverslip Place specimen in middle of slide Place drop of water on specimen Hold coverslip by thin edges between index finger and thumb 45 degree angle into drop of water

How to make a Wet Mount.. After water spreads along one edge of coverslip, slowly lower until it lies flat on top of slide IF bubbles appear, try again! Remove excess water with paper towels Add drop to edge if it dries out

Putting away Microscope… Switch to low power Place body tube all the way down towards the stage Wrap cord neatly Replace plastic bag on top

Microscope Sketches

Sketches: Sketch everything you can see Fill the appropriate amount of the circle based on your field of view Label your sketches Calculate total magnification for each sketch Give a brief description of each specimen’s appearance ALL sketches should be done on either medium or high power unless specified to sketch at low power

What to Sketch: Prepared slides (4 drawings needed) In packets: (part II) Letter “E” -- WET MOUNT Magazine picture – WET MOUNT Yarn (orange and black) – WET MOUNT #24: Butterfly wing (small piece of wing) – DRY MOUNT Feather – WET MOUNT Cat or human hair – WET MOUNT

Other Types of Microscopes

Other types of Microscopes… Electron microscope  Transmission electron m/s magnify images 250,000x’s Uses electron beams (no light) Uses electromagnetic lenses (no glass lenses) Electron beam directed via vacuum chamber: some pass through, some absorbed, some reflected – those transmitted through is what you see!

Other types of Microscopes… Electron microscope  Item must be dried, put in plastic, sliced into thin sections, and stained to view Scanning Electron Microscope magnify images 250,000x’s Uses electron beams (no light) Uses electromagnetic lenses (no glass lenses) Electron beam directed via vacuum chamber: some pass through, some absorbed, some reflected – those transmitted through is what you see! Stain increased amount of contrat