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The microscope
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- 2. MICROSCOPE A microscope isan instrument used to see objects that are too small for the naked eye. The science of investigating small objects using such an instrument is called microscopy. Microscopic means invisible to the eye unless aided by a microscope.
- 3. Parts and Functionsof a Compound Microscope
- 4. Light Microscope Uses singlelens Uses set lenses or a lens system SIMPLE COMPOUND
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- 7. Compound Microscope Mechanical PartsMagnifying Parts Illuminating Parts Adjustments and Support Enlarge the specimen Provide the light
- 8. Mechanical Parts o Base –Bottommost portion that supports the entire/lower microscope o Pillar – Part above the base that supports the other parts o Inclination Joint – Allows for tilting of the microscope for convenience of the user
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- 10. o Arm/Neck – Curved/slantedpart which is held while carrying the microscope o Stage – Platform where object to be examined is placed o Stage Clips – Secures the specimen to the stage Mechanical Parts
- 11. o Stage Opening oBody Tube – Attached to the arm and bears the lenses o Draw Tube – Cylindrical structure on top of the body tube that holds the ocular lenses Mechanical Parts
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- 13. o Revolving Nosepiece –Rotating disc where the objectives are attached o Dust Shield – Lies atop the nosepiece and keeps dust from settling on the objectives Mechanical Parts
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- 15. o Coarse AdjustmentKnob – Geared to the body tube which elevates or lowers when rotated bringing the object into approximate focus o Fine Adjustment Knob – A smaller knob for delicate focusing bringing the object into perfect focus
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- 17. • Condenser AdjustmentKnob – Elevates and lowers the condenser to regulate the intensity of light • Iris Diaphragm Lever – Lever in front of the condenser and which is moved horizontally to open/close the diaphragm Mechanical Parts
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- 19. Illuminating Parts o Mirror –Located beneath the stage and has concave and plane surfaces to gather and direct light in order to illuminate the object o Electric Lamp – A built-in illuminator beneath the stage that may eb used if sunlight is not preferred or is not available
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- 21. MAGNIFYING PARTS • Ocular/ Eyepiece – Another set of lens found on top of the body tube which functions to further magnify the image produced by the objective lenses. It usually ranges from 5x to 15x.
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- 23. MAGNIFYING PARTS • Objectives –Metal cylinders attached below the nosepiece and contains especially ground and polished lenses • SCANNER • LPO / Low Power Objective – Gives the lowest magnification, usually 10x • HPO / High Power Objective – Gives higher magnification usually 40x or 43x • OIO / Oil Immersion Objective – Gives the highest magnification, usually 97x or 100x, and is used wet either with cedar wood oil or synthetic oil
- 24. Total Magnification Magnification =Objective lens X Eyepiece lensMagnification = Objective lens X Eyepiece lens e.g. What is the total magnification if the objective lens is twenty times (X20) and the eyepiece lens five times (X5)? Magnification = 20 X 5 = X100
- 25. Asmagnification increases,detail increases but Onioncell 40x Onion cell 100x Onion cell 400x less of the cell is seen
- 26. Caring for theMicroscope 1. Do not let any liquids to come in contact with the microscope. 2. Always store the microscope inside a box after use. 3. Return the objective lens onto low power after use. 4. Carry the microscope by the arm. 5. Use a soft clean tissue to wipe the lenses
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- 28. Preparing a slide asa wet mount.
- 29. Useofstains some partsof a plant cell can be clearly seen when the cell is mounted in water E.g. an Elodea leaf cell: cell wall several chloroplasts
- 30. other cellstructures which are not so obvious can often be shown up more clearly by the addition of dyes called STAINS Iodine Solution Used to stain plant cells Methylene Blue Used to stain animal cells
- 31. A thin innerlayer of epidermis is peeled off. Snapping leaf backwards exposes the epidermis. Epidermis is placed on slide & covered with 2-3 drops of distilled water . Coverslip is lowered. A drop of stain is put at one end of slide. 1 An onion is cut into quarters. 2 One of the fleshy scale leaves is removed. 3 5 4 6 7 Stain is drawn over specimen using a small piece of filter paper.
- 32. How to makea wet-mount slide … 1 – Get a clean slide and coverslip from your teacher. 2 – Place ONE drop of water in the middle of the slide. Don’t use too much or the water will run off the edge and make a mess! 3 – Place the edge of the cover slip on one side of the water drop. You do not need to use the stage clips when viewing wet-mount slides! 5 – Place the slide on the stage and view it first with the red-banded objective. Once you see the image, you can rotate the nosepiece to view the slide with the different objectives. 4 - Slowly lower the cover slip on top of the drop. Cover Slip Lower slowly
- 33. Appearance of theSpecimen Objects appear upside-down&backward Movementappears tobein oppositedirectionthan actual movement 1 2 moveslide slideappearstomove 2 1
- 34. End -Sir Leomered P.Medina