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Introduction to Microscopy. ACC Biology 2015-2016. I. The Microscope. A. Major Parts of the microscope What commonly used type of microscope will be used in class? A : Compound Light Microscope The major parts of a microscope are sometimes referred to as the mechanical system.
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Introduction to Microscopy ACC Biology 2015-2016
I. The Microscope A. Major Parts of the microscope What commonly used type of microscope will be used in class? A : Compound Light Microscope • The major parts of a microscope are sometimes referred to as the mechanical system.
Our microscopes have 3 major objectives : 1. Scanning objective – shortest objective (red) with a lens that has a magnification of 4x. Always start here! 2. Low power objective – medium objective (yellow) with a lens that has a magnification of 10x. Used 2nd. 3. High power objective – longest objective (blue) with a lens that has a magnification of 40x. Used last.
B. Important Microscope Terminology 1. Illuminator – light source of a microscope. 2. Light system – light + diaphragm of microscope. 3. Magnification – the enlargement of an image. 4. Magnifying power – the extent to which a microscope magnifies images. Expressed as a # followed by a multiplication sign, ex : 100x. • Total magnification is found by multiplying the magnifying power of the objective lens by the magnifying power of the ocular lens, ex : 40 (high power obj.) x 10 (ocular power) = 400x (total magnification)
B. Important Microscope Terminology con’t. 5. Resolution – ability of a microscope to show two points that are close together as separate images. Also called resolving power. Refers to the sharpness or clarity of an image. *Most important characteristic. 6. Field of view – area that one sees when looking through a microscope. -Is commonly drawn as a circle when sketching images in a lab.
C. Preparation of Specimens & Slides 4 Methods of specimen preparation : 1. Fixation - done by cutting the material into small pieces & allowing it to soak in a fixative, such as formalin. 2. Embedding - placing in liquid wax or plastic & allowing it to harden. 3. Sectioning - slicing thinly, done by a microtome (special machine). 4. Staining - dying a specimen so that the structural details are easier to see.
Glass Slide Preparation for Labs : A. Creating a dry mount slide (No water needed on slide) 1. Place a small, flat object in the center of the microscope slide. 2. Place the edge of the coverslip to one side of the object & gently lower the slip onto the slide so that it covers the object.
Creating a Wet Mount Slide B. Creating a wet mount slide (Water used to make slide) 1. Place one drop of water in the center of the microscope slide. 2. Place the object being viewed in the center of the water drop. 3. Touch the edge of the coverslip to the surface of the slide at a 45 degree angle; gently lowering it to allow air to escape & to reduce development of air bubbles in the field of view.
