The Microscope

Essential question: How did microscopes change our ideas about living things?

The History Zacharias Jansen The “First” Microscope The first microscope was 6 feet long!!! The Greeks & Romans used “lenses” to magnify objects over 1000 years ago.

The History In the 1590”s, Hans and Zacharias Janssen of Holland created the “first” compound microscope Anthony van Leeuwenhoek and Robert Hooke made improvements by working on the lenses. %26GradeLevel%3d %26Page%3d2%26ID%3d Anthony van Leeuwenhoek Robert Hooke Hooke Microscope

How a Microscope Works Convex Lenses are curved glass used to make microscopes (and glasses etc.) Convex Lenses bend light and focus it in one spot.

6 Eye Piece (ocular) Body Tube Revolving Nose Piece Low Power Objective Coarse Focus Fine Focus Arm Stage Clips Pivot Point Base High Power Objective Stage Diaphragm Mirror

7 1) Eye Piece (ocular) –  the lens that you look through  the tube that supports the eyepiece 2) Body Tube –

8 Revolving 3) Revolving Nosepiece- the rotating device that holds and changes the objectives (lenses). Aperature- Opening in the stabe to allow light from mirror or light to pass

9  magnification lens with the lowest power 4) Low Power Objective – 6) Stage Clips – clips that keep the slide or specimen from moving on the stage  magnification lens with the highest power 5) High Power Objective –

10 7) Stage – holds the specimen

11 controls the amount of light entering through the aperature to the objectivefrom the bottom 8) Diaphragm-

12 Pivot Point Base Mirror 9) Pivot Point- supports the microscope 11) Mirror 10) Base- reflects (bends) the light upward onto the slide part that allows you to tip the ocular toward you

13 12) Fine Focus Adjustment – 13) Coarse Focus Adjustment- 14) Arm – moves the body tube in small increments moves the body tube in large increments attaches the eyepiece and the body tube to the base

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Magnification To determine your magnification…you just multiply the ocular lens by the objective lens 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”

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

19 Elodea 40 x Elodea 100x Elodea 400x

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

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

Microscope Lab

Using a Microscope Always start on the lowest magnification (4X) Don’t use the coarse adjustment knob on high magnification…you’ll break the slide and damage the lenses!!! Don’t prepare slides/wetmounts on the stage– water will damage the microscope and you could get electricuted . Place slide on stage and clip it in after finding and centering the image. Adjust light going through the diaphragm according to teacher’s direction. Clean with special lens tissue, carry with two hands, & be careful of the light falling out  …

Preparing a wet mount of the letter “e". With your scissors cut out the letter "e" from the newspaper. Place it on the glass slide so as to look like (e). Cover it with a clean cover slip. See the figure below. ***Place the slide on a paper towel on the lab table to prepare webmount. Using your eyedropper, place a drop of water on the edge of the cover slip where it touches the glass slide. The water should be sucked under the slide if done properly. Wipe off excess water before placing slide on the stage of the microscope 24 e

The End… any questions?

26 STOP: TEACHER NOTES & ADDITIONAL PICS

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