MICROSCOPES

Compound light microscopes are delicate precision

instruments. Be gentle.

Ms O'Connell 1

Word Parts

• micro – very small • macro – large • scope – to see

Ms O'Connell 2

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'Connell 3

• 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'Connell 4

ALWAYS start by using the low-power objective.

BIG + BIG = BAD

Ms O'Connell 5

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'Connell 6

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'Connell 7

• 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'Connell 8

Resolution (Resolving Power)

Ms O'Connell 9

• 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'Connell 10

• 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'Connell 11

Depth of Focus Fibers

Ms O'Connell 12

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'Connell 13

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'Connell 14

• Dissecting microscope: – Also called a stereo

microscope– Used for macro

objects (e.g., bugs)

Ms O'Connell 15

• Transmission electron microscope (TEM): Electrons pass through a thin sliced specimen.

Ms O'Connell 16

• Scanning electron microscope (SEM): Electrons are directed at the surface of the specimen.

Ms O'Connell 17

Acanthus anther with pollen

Ms O'Connell 18

Ms O'Connell 19

Ms O'Connell 20