MICROSCOPES Compound light microscopes are delicate precision instruments. Be gentle. Ms O'Connell1

Word Parts micro – very small macro – large scope – to see Ms O'Connell2

CARE AND USE NEVER force the controls. Use a clean, dry lens tissue on the glass surfaces. Lift by grasping the arm and the base. Set the microscope down gently. Ms O'Connell3

Place the microscope away from the edge of the table. Don’t let the cord hang over the edge of the table. Slides are usually made of glass and may break. Be careful of sharp edges. Ms O'Connell4

 ALWAYS start by using the low-power objective. BIG + BIG = BAD Ms O'Connell5

VOCABULARY Power of magnification: The relative enlargement of the specimen when seen through the microscope. – The power of magnification can be calculated by multiplying the power of the eye piece lens by the power of the objective lens. Ms O'Connell6

 Inversion: The reversal of the specimen image by the microscope lenses.  A specimen that appears upside down when being viewed is actually right-side up on the slide.  Moving the specimen to the right causes its image to move to the left. Likewise, moving it down causes it to move upward. Ms O'Connell7

Resolution (resolving power): The smallest distance separating two objects that allows them to be seen as two distinct things rather than as a single entity. Ms O'Connell8

Resolution (Resolving Power) Ms O'Connell9

Working distance: The distance between the tip of the objective and the top of the cover glass on the slide. The higher the magnification the smaller the working distance. Ms O'Connell10

Depth of focus: The thickness of a specimen which may be seen in focus at one time. The greater the power of magnification the lesser the depth of focus. Ms O'Connell11

Depth of Focus Fibers Ms O'Connell12

 Field of vision: The surface area which can be seen when looking through the light microscope. The area decreases with increasing power of magnification. Ms O'Connell13

TYPES OF MICROSCOPES Compound light microscope – Glass lenses focus a beam of light on the specimen – Used to view cells and some organelles Ms O'Connell14

Dissecting microscope: – Also called a stereo microscope – Used for macro objects (e.g., bugs) Ms O'Connell15

Transmission electron microscope (TEM): Electrons pass through a thin sliced specimen. Ms O'Connell16

Scanning electron microscope (SEM): Electrons are directed at the surface of the specimen. Ms O'Connell17 Acanthus anther with pollen

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