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Microscopy Light and Electron Microscopy. The History Many people experimented with making microscopes Many people experimented with making microscopes.

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Presentation on theme: "Microscopy Light and Electron Microscopy. The History Many people experimented with making microscopes Many people experimented with making microscopes."— Presentation transcript:

1 Microscopy Light and Electron Microscopy

2 The History Many people experimented with making microscopes Many people experimented with making microscopes Was the microscope originally made by accident? (Most people were creating telescopes) Was the microscope originally made by accident? (Most people were creating telescopes) The first microscope was 6 feet long!!! The first microscope was 6 feet long!!! The Greeks & Romans used “lenses” to magnify objects over 1000 years ago. The Greeks & Romans used “lenses” to magnify objects over 1000 years ago.

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

4 The History Zacharias Jansen The “First” Microscope

5 The History Hans and Zacharias Janssen of Holland in the 1590’s created the “first” compound microscope Hans and Zacharias Janssen of Holland in the 1590’s created the “first” compound microscope Anthony van Leeuwenhoek and Robert Hooke made improvements by working on the lenses Anthony van Leeuwenhoek and Robert Hooke made improvements by working on the lenses Anthony van Leeuwenhoek Robert Hooke Hooke Microscope

6 How a Microscope Works Ocular 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).

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

8 The Parts of a Light Microscope Light source: Could be a mirror, but most likely it is a bulb built into the base Light source: Could be a mirror, but most likely it is a bulb built into the base Diaphragm: Adjusts the amount of light striking an object Diaphragm: Adjusts the amount of light striking an object Objective lens: Gathers light and magnifies image Objective lens: Gathers light and magnifies image Ocular lens (eyepiece): Magnifies objects and focuses light to your eye Ocular lens (eyepiece): Magnifies objects and focuses light to your eye Stage: Holds slide Stage: Holds slide Can be moved using the coarse or fine adjustment knobs to bring the object into focus Can be moved using the coarse or fine adjustment knobs to bring the object into focus Stage clips: Hold slide in place Stage clips: Hold slide in place Base and arm: Structural support for the microscope Base and arm: Structural support for the microscope

9 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 Lenses Stage Diaphragm Light Source Base Fine adjustment Course adjustment Stage clip Arm Ocular lens (eyepiece)

10 Images Produced by Light Microscopes AmoebaStreptococcus bacteriaAnthrax bacteria Human cheek cells Plant cells Yeast cells

11 Resolution pp Resolution : the ability to distinguish between two objects that are very close together Resolution : the ability to distinguish between two objects that are very close together

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

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14 Types of Electron Microscopes Specimens from electron microscopy must be preserved and dehydrated, so living cells cannot be viewed Specimens from electron microscopy must be preserved and dehydrated, so living cells cannot be viewed Transmission electron microscopes (TEMs) pass a beam of electron through a thin specimen Transmission electron microscopes (TEMs) pass a beam of electron through a thin specimen Scanning electron microscopes (SEMs) scan a beam of electrons over the surface of a specimen Scanning electron microscopes (SEMs) scan a beam of electrons over the surface of a specimen

15 Images Produced by Electron Microscopes Cyanobacteria (TEM) Lactobacillus (SEM) Campylobacter (SEM) Deinococcus (SEM) House ant Avian influenza virus Human eyelash Yeast

16 Using Microscopes to Visualize the Three Shapes of Bacteria Cocci (round) Cocci (round) Bacilli (rod) Bacilli (rod) Spirilla (spiral) Spirilla (spiral) Light microscope: Three shapes of bacteria taken with an SEM Bacilli Cocci Spirilla

17 Magnification To determine your magnification…you just multiply the ocular lens by the objective lens To determine your magnification…you just multiply the ocular lens by the objective lens Ocular 10x Objective 40x:10 x 40 = 400 Ocular 10x Objective 40x:10 x 40 = 400 Objective Lens have their magnification written on them. Ocular lenses usually magnifies by 10x So the object is 400 times “larger”

18 Caring for a Microscope Clean only with a soft cloth/tissue Clean only with a soft cloth/tissue Make sure it’s on a flat surface Make sure it’s on a flat surface Don’t bang it Don’t bang it Carry it with 2 HANDS…one on the arm and the other on the base Carry it with 2 HANDS…one on the arm and the other on the base

19 Carry a Microscope Correctly

20 Using a Microscope Start on the lowest magnification Start on the lowest magnification Don’t use the coarse adjustment knob on high magnification…you’ll break the slide!!! Don’t use the coarse adjustment knob on high magnification…you’ll break the slide!!! Place slide on stage and lock clips Place slide on stage and lock clips Adjust light source (if it’s a mirror…don’t stand in front of it!) Adjust light source (if it’s a mirror…don’t stand in front of it!) Use fine adjustment to focus Use fine adjustment to focus

21 Calculations Field of View : whole circular area that you see when you look through the microscope Field of View : whole circular area that you see when you look through the microscope Total Magnification : ocular (10x) times the objective lens Total Magnification : ocular (10x) times the objective lens Low power : 10x * 4x = 40x Low power : 10x * 4x = 40x Medium power : 10x * 10x = 100x Medium power : 10x * 10x = 100x High power : 10x * 40x = 400x High power : 10x * 40x = 400x Field Diameter : distance across the field of view Field Diameter : distance across the field of view Low power [40x] = 4.5 mm = μm Low power [40x] = 4.5 mm = μm Medium power [100x] = 1.8 mm = μm Medium power [100x] = 1.8 mm = μm High power [400x] = 0.45 mm = 450 μm High power [400x] = 0.45 mm = 450 μm

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

23 Calculating Estimated Actual Size of a Specimen Field diameter Determine by evaluating which objective lens was used to view specimen Ensure units are μm # of specimens fitting across field diameter Estimate how many specimens fit across the field diameter width wise

24 Calculating Estimated Actual Size of a Specimen Field diameter Viewed under medium power Field of View is μm # of specimens fitting across field diameter estimate 3 times across

25 Calculating Magnification of a Drawing Width of drawing Use a ruler to measure your drawing width-wise Convert you units to μm Actual size of specimen See previous slides

26 Biological Drawings What you need: What you need: Blank paper Blank paper Sharp pencil Sharp pencil Ruler Ruler Labels Labels Neatly printed Neatly printed To the right To the right Even column Even column Parallel lines/do not cross Parallel lines/do not cross Ruler used Ruler used Use firm clear lines Use firm clear lines No shading/colour No shading/colour Large drawing Large drawing Underline titles Underline titles Top right corner: name & date Top right corner: name & date Bottom right corner: total magnification Bottom right corner: total magnification

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29 References oducts_id=1123 oducts_id=1123 oducts_id=1123 oducts_id= Google Images Google Images


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