Microscopes

Some Microscope Parts

Some Microscope Parts(lens to ‘see’ through;Magnifies 10x)

(Carry microscope)

(Carry microscope)

(lenses close to object/specimen;Magnifies 10x, 20x, or 40x)

NOSE PIECE(select objective lens)

STAGE (holds slide)

(Lifts or lowers stage to produce a focused image) (focuses/condenses

light on specimen)

(a.k.a body tube/keeps eyepiece at correct distance from objective)

(sharpens focus)

Iris Diaphragm (open 1/close 5) • Can be used to increase contrast (close 5)

• Or increase amount of light (open 1)

Diaphragm

Stage Clips

Diaphragmlever

Magnifying Power

Eyepiece x objective lens = TOTAL magnification

– LOW POWER: 10x X 10x = 100x

– HIGH POWER: 10x X 43x = 430x

• correct units for a microscope = micrometer (µm)

• 1 µm = (1/1000) mm

KEEP IT CLEAN!

• When to use…

Objective lens

Glass slides

Cover slips

Condenser Eye piece

Lens tissue

Slide tissue

X

X X

X X

Sequence for Viewing

1. plug in & turn on

2. find object in LOW POWER

3. focus with coarse adjustment & adjust light (light: 1 lets in the most & 5 least)

4. center object (still in low power)

5. turn to high power objective without changing focus

6. re-adjust light

7. sharpen focus with fine adjustment

PARFOCAL

• ability for the microscope to remain in focus when objective lens is changed

Low powerHigh Power

Make a “Wet Mount”

Cover slip

Lower

Slide

1

2

Store your Microscope Properly

1. Take slide OFF

2. Put lower power above stage

3. Roll nosepiece up (old); Stage down (new)

4. Turn OFF light

5. Wrap cord around scope

How not to break the microscope

• Always carry the microscope with 2 hands, one hand under the base & the other grasping the arm.

Discussion and Summary

H A F Appears on stage

H

A F Appears in theEyepiece

It _____________________

It turns it _______________

& _____________________

What a microscope does to an image…

Magnifies

Upside down

Backwards

As the power of the microscope

• Magnification increases

– The field of vision – The depth of field – Amount of light passing through the lens

system

0.2m

0.1nm