MicroscopyLight and Electron Microscopy

The HistoryMany people experimented with making microscopes

Was the microscope originally made by accident? (Most people were creating telescopes)

The first microscope was 6 feet long!!!

The Greeks & Romans used lenses to magnify objects over 1000 years ago.

The First Light MicroscopesAround 1590 Zaccharias and Hans Janssen experimented with lenses in a tube, leading to the forerunner of the microscope and the telescopeIn the late 1600s, Anton van Leeuwenhoek was the first to see bacteria, yeast, and many other microbes using a microscope

The HistoryZacharias Jansen1588-1631 The First Microscope

The HistoryHans and Zacharias Janssen of Holland in the 1590s created the first compound microscopeAnthony van Leeuwenhoek and Robert Hooke made improvements by working on the lenses

Anthony van Leeuwenhoek1632-1723Robert Hooke 1635-1703 Hooke Microscope

How a Microscope WorksOcular Lens(Magnifies Image)Objective Lens(Gathers Light, Magnifies And Focuses Image Inside Body Tube)Body Tube(Image Focuses)Bending Light: The objective (bottom) convex lens magnifies and focuses (bends) the image inside the body tube and the ocular convex (top) lens of a microscope magnifies it (again).

How to Use A Light MicroscopeFirst, the objective lens gathers light from the specimen and magnifies the imageMost microscopes have several objective lenses that can be rotated into position to provide different levels of magnification (4X, 10X, 40X)The ocular lens in the eyepiece magnifies and transmits the image to your eyeThe magnification of the ocular lens is 10XTo find the total magnification of the microscope you are using, multiply the magnification of the objective lens by the magnification of the ocular lens. For example: 40X (objective lense) x 10X (ocular lense) = 400X magnification

The Parts of a Light MicroscopeLight source: Could be a mirror, but most likely it is a bulb built into the baseDiaphragm: Adjusts the amount of light striking an objectObjective lens: Gathers light and magnifies imageOcular lens (eyepiece): Magnifies objects and focuses light to your eyeStage: Holds slideCan be moved using the coarse or fine adjustment knobs to bring the object into focus Stage clips: Hold slide in placeBase and arm: Structural support for the microscope

Can you name the parts?Start on the left side and work from the top down. Then go to the right side and work from the top down.Nice Job !Objective LensesStageDiaphragmLight SourceBaseFine adjustmentCourse adjustmentStage clipArmOcular lens (eyepiece)

Images Produced by Light MicroscopesAmoebaStreptococcus bacteriaAnthrax bacteriaHuman cheek cellsPlant cellsYeast cells

Resolution pp.18-19Resolution : the ability to distinguish between two objects that are very close together

Beyond Light MicroscopesLight microscopes are limited by their resolution.Light microscopes cannot produce clear images of objects smaller than 0.2 micrometersThe electron microscope was invented in the 1930s by Max Knott and Ernst RuskaElectron microscopes use beams of electrons, rather than light, to produce imagesElectron microscopes can view objects as small as the diameter of an atom

Types of Electron MicroscopesSpecimens from electron microscopy must be preserved and dehydrated, so living cells cannot be viewedTransmission electron microscopes (TEMs) pass a beam of electron through a thin specimenScanning electron microscopes (SEMs) scan a beam of electrons over the surface of a specimen

Images Produced by Electron MicroscopesCyanobacteria (TEM)Lactobacillus (SEM)Campylobacter(SEM)Deinococcus(SEM)House antAvian influenza virusHuman eyelashYeast

Using Microscopes to Visualize the Three Shapes of BacteriaCocci (round)Bacilli (rod)Spirilla (spiral)

Light microscope:Three shapes of bacteria taken with an SEMBacilliCocciSpirilla

MagnificationTo determine your magnificationyou just multiply the ocular lens by the objective lensOcular 10x Objective 40x:10 x 40 = 400Objective Lens have their magnificationwritten on them.Ocular lenses usually magnifies by 10xSo the object is 400 times larger

Caring for a MicroscopeClean only with a soft cloth/tissue

Make sure its on a flat surface

Dont bang it

Carry it with 2 HANDSone on the arm and the other on the base

Carry a Microscope Correctly

Using a MicroscopeStart on the lowest magnificationDont use the coarse adjustment knob on high magnificationyoull break the slide!!!Place slide on stage and lock clipsAdjust light source (if its a mirrordont stand in front of it!)Use fine adjustment to focus

CalculationsField of View : whole circular area that you see when you look through the microscopeTotal Magnification : ocular (10x) times the objective lensLow power : 10x * 4x = 40xMedium power : 10x * 10x = 100xHigh power : 10x * 40x = 400xField Diameter : distance across the field of viewLow power [40x] = 4.5 mm = 4 500 mMedium power [100x] = 1.8 mm = 1 800 mHigh power [400x] = 0.45 mm = 450 m

Finding Field DiameterIf you find field diameter on a low power magnification, you can use this to calculate the field diameter at higher magnifications

Calculating Estimated Actual Size of a SpecimenField diameterDetermine by evaluating which objective lens was used to view specimenEnsure units are m

# of specimens fitting across field diameterEstimate how many specimens fit across the field diameter width wise

Calculating Estimated Actual Size of a SpecimenField diameterViewed under medium powerField of View is 1 800 m

# of specimens fitting across field diameter estimate 3 times across

Calculating Magnificationof a DrawingWidth of drawingUse a ruler to measure your drawing width-wiseConvert you units to m

Actual size of specimenSee previous slides

Biological DrawingsWhat you need:Blank paperSharp pencilRulerLabelsNeatly printedTo the rightEven columnParallel lines/do not crossRuler used

Use firm clear linesNo shading/colourLarge drawingUnderline titles

Top right corner: name & dateBottom right corner: total magnification

Referenceshttp://education.denniskunkel.com/catalog/product_info.php?products_id=1123http://micro.magnet.fsu.edu/http://inventors.about.com/library/inventors/blroberthooke.htmhttp://www.cerebromente.org.br/n17/history/neurons1_i.htmGoogle Imageshttp://science.howstuffworks.com/light-microscope1.htm

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