Parts of a Microscope

Microscope Basics

Label the Compound Light Microscope(Handout)

Ocular lens

Body TubeCoarse Adjustment KnobFine adjustment KnobRevolving nosepieceObjective lenses (4x, 10x, 40x)ArmStage Stage ClipsDiaphramLight source

Base

Taking a look at the world…. Look around the room….What types of things can you see in plain view (with your eyes)?

Now, use the hand-held magnifying glass….What new things can you see?

What types of things might you see if these things were magnified, 10x, 40x, 100x, 10 000x or even 1 000 000x?

Field of view and Magnification

Microscope History and Development

Microscope HistoryAnton Van Leeuwenhoek

The father of microscopyfirst to see and describe bacteria.

Robert HookeRobert Hooke: sees cork through a

microscope lens and noticed some "pores" or "cells" in it.

First person to use the word "cell”

Technological Advances in Microscopes

Compound Light Microscope

• Uses light• Has two lenses• Magnification is limited to 2000x• We use this type at LHHS (our

magnification is 400x)

Transmission Electron Microscope (TEM)

Uses beams of electronsMagnification of 2 000 000xHas two limitations:

Good only for thin specimensOnly dead cells can be observed

Scanning Electron Microscope (SEM)

Electrons are reflected from the surface of the specimen

Produces a 3-d imageGood for the thicker specimensLacks the magnification and resolution of the

transmission electron microscope

SEM

Guess the Picture: These are images using a SEM microscope!• Cat flea

SEM

• Mosquito head

SEM

• Porcupine Quill

SEM

• Toilet Paper

SEM

• Mascara Brush

SEM

• Mosquito Head Close-up

SEM

• Foot of a house fly

SEM

• Dentist Drill

SEM

• Velcro

MagnificationMagnification = Objective lens X

Ocular lens(4x, 10x, 40x)

(10x)

Calculating the size of a specimenbinder

Calculating the size of a specimenExample under med. objective

Object size = Size of field of viewNumber of objects across field of view

Object size = 1.72 mm 14

Object size = 0.1 mm