The Microscope

Light Microscope

Microscope Parts: Ocular lens (Eyepiece) used to look through has a magnification of 10X

Microscope Parts: b. Objective Lenses Offer more magnification There are three lenses we will use in our class. Scanning Objective 4x Low Power 10x High Power 40x

Calculating Magnification: Simply multiply the eye piece magnification by the objective lens magnification. EX: A 10x eyepiece X 40x objective = 400x Now try the other examples below!

Magnification: 400x 40x 100x Magnification Ocular Lens Total Magnification Scanning 4x 10x Low Power High Power 40x 40x 100x 400x

Microscope Parts Cont’d: c. Body tube – holds the eyepiece d. Arm – used for grasping when carrying e. Base – support f. Revolving Nosepiece – turns the objective lenses.

Microscope Parts Cont’d: g. Stage – platform on which specimen or slide is placed h. Stage clips – hold the slide in place

Microscope Parts Cont’d: i. Coarse Adjustment (Large knob) – causes large movement. use under low power j. Fine Adjustment (small knob) – causes small movement use under high power

Microscope Parts Cont’d: k. Diaphragm – controls the amount of light passing through the specimen l. Light Source (illuminator) – provides the light which must pass through the object to be studied

Light Microscope

II. Microscope Safety: Notify teacher if a slide or cover slip breaks. Always carry the microscope with two hands - one on the arm and one underneath the base of the microscope. Do not touch the lenses. If using a microscope with a light, turn the microscope off, when not in use.   Notify teacher if a slide or cover slip breaks.

III. Focusing Specimens: Always start with the scanning objective. 2. Use the Coarse Adjustment Knob to focus, image may be small at this magnification

Focusing Cont’d: 3. Once you've focused on Scanning (4x), switch to Low Power (10x). 4. Use the Coarse Adjustment Knob to refocus.

Focusing Cont’d: 5. Now switch to High Power. 6. STOP!!!! At this point, ONLY use the Fine Adjustment Knob to focus specimens. If the specimen is too light or too dark, try adjusting the diaphragm.

Images viewed under the light microscope are reversed (backward) and inverted (upside down).  

IV. Making a Wet Mount Slide Gather a thin slice/piece of whatever your specimen is. Place ONE drop of water directly over the specimen.

Place the coverslip at a 45o angle with one edge touching the water drop and then gently let go.

The End

Staining

How to Stain a Slide: Place ONE drop of stain (iodine, methylene blue) on the edge of the coverslip. Place the flat edge of a piece of paper towel on the opposite side of the coverslip. The paper towel will draw the water out from under the coverslip, and the cohesion of water will draw the stain under the slide.

Staining… As soon as the stain has covered the area containing the specimen, you are finished.