Introduction to Introduction to Microscopes!Microscopes!

Now Seeing Now Seeing ISIS Believing! Believing!

A Brief HistoryA Brief History

Simple Glass MagnifiersSimple Glass Magnifiers

More than 500 years ago.More than 500 years ago. In 1600s, this “simple microscope” In 1600s, this “simple microscope”

allowed scientists to see cells and allowed scientists to see cells and bacteriabacteria

Problem: not enough Problem: not enough magnification magnification

First Compound First Compound MicroscopeMicroscope

Developed at the beginning of the Developed at the beginning of the 1600's, by the Janssen brothers and 1600's, by the Janssen brothers and GalileoGalileo

Problem: images Problem: images were blurred and were blurred and had had colored haloscolored halos

Simple Compound Simple Compound MicroscopeMicroscope

Invented in Invented in 1660s1660s

Problem: Problem: all images all images had red or had red or blue blue “halos” “halos” around around themthem

Even better!Even better!

1700 and 1800s – 1700 and 1800s – great improvement great improvement in microscopesin microscopes

Usually made of Usually made of brass (expensive)brass (expensive)

Had a tripod for Had a tripod for supportsupport

Modern Compound Modern Compound MicroscopeMicroscope

1900s, started using iron 1900s, started using iron instead of brass (cheaper) instead of brass (cheaper)

Only one eyepiece Only one eyepiece (monocular) (monocular)

Outside light source Outside light source reflected onto mirror reflected onto mirror

Very functionalVery functional Still used todayStill used today

Fancy!Fancy!

Better imagesBetter images More More

magnificationmagnification Better lightingBetter lighting Easier to useEasier to use Now everyone, Now everyone,

at one time or at one time or another, has another, has looked through looked through a microscopea microscope

How Does It Work?How Does It Work? A microscope works very much like a A microscope works very much like a

telescope.telescope. A telescope must gather light from a dim, A telescope must gather light from a dim, far far

awayaway object. object. So, it needs a So, it needs a largelarge

objective lens to objective lens to gather as much gather as much light light as possible and a as possible and a longlong body to bring body to bring the image into focus. the image into focus.

How Does It Work?How Does It Work? Unlike a telescope, a Unlike a telescope, a

microscope must gather microscope must gather light from a light from a tinytiny specimen specimen that is that is close-byclose-by. .

So the microscope does So the microscope does notnot need a large objective lens. need a large objective lens.

Instead, the Instead, the objective lensobjective lens of a microscope is of a microscope is smallsmall..

Then the image is again Then the image is again magnified by a second lens, magnified by a second lens, called an called an eyepieceeyepiece, as it is , as it is brought to your eye. brought to your eye.

Parts of a Compound Parts of a Compound MicroscopeMicroscope

So EASY a KID could use it!

BaseBase

The bottom of The bottom of the the microscope, microscope, used for used for supportsupport

Hold this part Hold this part with one hand with one hand when carrying when carrying a microscopea microscope←←

MirrorMirror

Reflects the Reflects the light so the light so the specimen is specimen is easier to seeeasier to see

←←

StageStage

The flat The flat platform platform where you where you place your place your slides.  slides. 

It has a hole It has a hole in it so light in it so light can shine can shine throughthrough

←←

ClipClip

Shiny clips Shiny clips on the top of on the top of the stagethe stage

Holds a slide Holds a slide in placein place

←←

ArmArm

Supports the Supports the tube and tube and connects it to connects it to the base the base

The part you The part you hold when hold when you carry the you carry the microscopemicroscope

←←

Coarse AdjustmentCoarse Adjustment Large, round Large, round

knob on the knob on the side of the side of the microscopemicroscope

Either moves Either moves the stage or the the stage or the top part of the top part of the microscope up microscope up and downand down

Use only on Use only on Low PowerLow Power

→→

Fine AdjustmentFine Adjustment Small, round Small, round

knob on the side knob on the side of the microscopeof the microscope

Used to fine tune Used to fine tune the focus after the focus after using the coarse using the coarse adjustment knob.adjustment knob.

Use on all Use on all Objective lenses Objective lenses except Low except Low PowerPower

→→

EyepieceEyepiece

The lens at The lens at the top that the top that you look you look through.through.

10X10X power power

→→

Body TubeBody Tube

The long tube The long tube that holds the that holds the eyepiece and eyepiece and connects the connects the objectiveobjective

→→

NosepieceNosepiece

Rotating part Rotating part of the of the microscope at microscope at the bottom of the bottom of the body tube.the body tube.

It holds the It holds the objective objective lenseslenses

←←

High Power ObjectiveHigh Power Objective

The longest The longest objective lensobjective lens

The highest The highest magnificationmagnification

40X lens 40X lens (40X (40X xx 10X10X = = 400X 400X magnification)magnification)

→→

Low Power ObjectiveLow Power Objective

The shortest The shortest objective lensobjective lens

The lowest The lowest magnificationmagnification

4X lens 4X lens (4X (4X xx 10X10X = = 40X40X magnificationmagnification))

←←

Mid Power ObjectiveMid Power Objective

The medium The medium length length objective lensobjective lens

The medium The medium magnificationmagnification

10X lens 10X lens (10X (10X xx 10X10X = = 100X100X magnification)magnification)

←←

DiaphragmDiaphragm

Controls the Controls the amount of amount of light going light going through the through the hole in the hole in the stagestage

→→

Pop QuizPop Quiz1.1. What two parts What two parts

should you hold when should you hold when you carry a you carry a microscope?microscope?Base & ArmBase & Arm

2.2. Where do you put a Where do you put a slide?slide?On the StageOn the Stage

3.3. To focus, what knob To focus, what knob do you turn first? do you turn first? Second?Second?First, Coarse First, Coarse

AdjustmentAdjustment

Second, Fine Second, Fine AdjustmentAdjustment

←←

←←→→

←←←←

Test Your Skills . . . Test Your Skills . . .

ArmArm Body TubeBody Tube StageStage ClipClip Base Base Coarse Coarse

AdjustmentAdjustment Fine AdjustmentFine Adjustment

Test Your SkillsTest Your Skills

High Power High Power ObjectiveObjective

Low Power Low Power ObjectiveObjective

MirrorMirror EyepieceEyepiece NosepieceNosepiece DiaphragmDiaphragm