Exercise #2: The Microscope

Label the microscope

1) Arm

2) Base

3) In base illuminator (light source)

4) Condenser

5) Iris diaphragm and lever

6) Mechanical stage

7a) Slide positioner

7b) Adjustment knobs

8) Ocular lens/es (10x)

9) Rotating nosepiece

10) Objective lenses

• 10a) low power objective (4x)

• 10b) medium power objective (10x)

• 10c) high power objective (40x)

11a) Coarse focus adjustment knobs

11b) Fine focus adjustment knobs

What is the function of the in-base illuminator (light source)

provides even, high intensity light, that travels through the condenser to the specimen

What is the function of the condenser?

concentrates light from the illuminator onto the specimen

What is the function of the iris diaphragm and lever

The iris diaphragm regulates how much light is on the specimen

What is the function of the mechanical stage

allows for precise and controlled movement of the specimen slide

What is the function of the slide positioner and adjustment knobs?

holds the slide in place

moves the slide vertically or horizontally

What is the function of the ocular lenses?

How much does it magnify?

magnifies 10x the image produced by the objective lens and produces a virtual image

What is the function of the rotating nose piece?

holds objectives, rotates to change amount of magnification

What are the objective lens/es and their function?

How much do they magnify?

gathers light from a specimen, magnifies it, and forms an inverted image, further magnified by the ocular lens

low power objective (4x)

medium power objective (10x)

high power objective (40x)

How do you calculate the total magnification?

objective lens magnification x ocular lens magnification

What are the functions of the coarse and fine focus adjustment knobs?

A rapid control which allows for quick focusing

• initial focusing

A slow but precise control used to fine focus

• viewing at higher magnifications

What is field of view?

the illuminated area that you can see when you look into the microscope

As magnification decreases FOV gets?

smaller

FOV - inverse relationship

Low Power

Medium Power

High Power

Large FOV

Medium FOV

Small FOV

What is depth of field?

How much of a specimen is in focus

DOF- inverse relationship

Low Power

Medium Power

High Power

Large DOF

Medium DOF

Small DOF

The iris diaphragm can have an effect on?

The depth of field

What is the total magnification

ocular lenses x objectives

LO = 40x

MO = 100x

HO = 400x