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Set up Cornell Notes on pg. 51
Topic: How to Use a Microscope Essential Question: What can happen if you break the GOLDEN RULE of microscopes? How to Use a Microscope What can happen if you break the GOLDEN RULE of microscopes?
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Introduction to the Microscope
Students will have their microscopes out, for reference as we go through each of the steps. As an introduction, students will be asked what kinds of things they can do with this tool.
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Microscope Care Always carry with 2 hands
Only use lens paper for cleaning Do not force knobs Always store covered Keep objects clear of desk and cords Teacher demonstrates how to hold the microscope, where the lens paper is located and how to use it. Students will be invited to turn the knobs and observe the stage as it moves up and down. Teacher will demonstrate how to store the microscope.
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Microscope Parts Eyepiece Body Tube Revolving Nosepiece Body/Arm
Objective Lens Stage Stage Clips Coarse Focus This is the exact version of the microscope used in class. Students will be identifying the parts on the microscopes at their desks as we go along and what their functions are. Diaphragm/Light Adjust Fine Focus Light Base
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1. Control low power objective (short) 2. Place slide on stage
Using the Microscope 1. Control low power objective (short) 2. Place slide on stage 3. Focus all the way down 4. Focus using big knob 5. Change magnification Give students a slide from the “common things” set, each student will practice focusing and changing objectives.
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6. When using High power, NEVER EVER touch the big focus knob
Using the Microscope THE GOLDEN RULE 6. When using High power, NEVER EVER touch the big focus knob Give students a slide from the “common things” set, each student will practice focusing and changing objectives.
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Guidelines for Using the Light Microscope
Microscopes are expensive instruments. They must be handled with care in order to avoid damage. Keep the instrument in a box or under a cover when not in use. Use only the supporting arm of the microscope to lift it. Next >
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Eyepiece x Objective= TOTAL Magnification
If a ×10 objective lens is used, assuming the eye piece magnification is ×10, the total magnification of the image will be (×10) × (×10) = ×100. Eyepiece x Objective= TOTAL Magnification Next >
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Use the short lens first!!!!!
Select the Lowest Power Objective Lens It is normal practice to look at a specimen at the lowest available resolution first, then to look more closely at the specimen under a higher resolution. Use the short lens first!!!!! Next >
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Placing the Slide on the Stage
Place the slide on the stage, so that the specimen is over the middle of the hole on the stage. Make sure that light is shining through it and then secure it in place with the clips. Next >
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Lowering the Objective Lens
Look at the stage and the slide from the side. Then lower the objective lens using the coarse focus dial. Lower the lens until it is about 5 mm above the slide. This is to ensure that the slide is not crushed and damaged by the objective lens. Next >
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Getting the Specimen into Focus
Looking through the microscope eye piece, use the coarse focus dial to move the objective lens slowly upwards (never downward, as you could easily crush and break the slide). Do this until the specimen comes into focus. Try to keep both eyes open. This will help to prevent eye strain and headaches. Next >
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Adjusting the Diaphragm
The diaphragm can be adjusted to let different amounts of light through the specimen. This is because specimens vary in thickness. Finding the amount of light that produces the best viewing results for each specimen is often a matter of trial and error. Next >
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Minor Focusing Adjustments
The fine focus dial alters the height of the stage more accurately than the coarse focus dial. You may need to make minor adjustments to the objective lens using the fine focus dial to get your specimen into sharp focus. Next >
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Biological Drawings There are two main reasons why it is useful to make drawings of biological specimens: As a record of what you have seen As a way of studying the specimen in more detail Next >
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Using High Power Follow steps to focus using low power
Click the nosepiece to the longest objective Do NOT use the Coarse Focusing Knob Use the Fine Focus Knob to bring the slide Have students exchange slides so they can look at different things, walk them through using the high power objective to focus slides. Emphasize not using the coarse objective during this process, as it will crack the slides. What can you find on your slide?
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Steps for Cleanup 1. Center the low power objective (short lens)
2. Remove slide 3. Focus all the way down 4. Unplug cord 5. Wrap cord 6. Put cover back on Have students exchange slides so they can look at different things, walk them through using the high power objective to focus slides. Emphasize not using the coarse objective during this process, as it will crack the slides.
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Label The Microscope Parts
Eyepiece Body Tube Revolving Nosepiece Body/Arm Objective Lens Stage Stage Clips Coarse Focus This is the exact version of the microscope used in class. Students will be identifying the parts on the microscopes at their desks as we go along and what their functions are. Diaphragm/Light Adjust Fine Focus Light Base
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What are you looking at? Sordaria= fungus Volvox= green algae
Rbizopus w.m.= bread mold Human sperm smear= sperm Zea Mays Stem = corn stem Allium Root Tip = onion root tip Epithelia= simple cuboidal kidney tubules Spirogyra Vegatative = Green algae Tilia Stem = type of tree stem Plasmodium Falciparum= Protozoan Parasite that causes Malaria in humans Diatom= algae Lilium leaf= Lilly leaf Fasciola Hepatica- Parasitic flatworm that infects the liver and causes “liver rot”
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