How are Microscopes Used? Micro “tiny” – scope “to view” How big is a….. Can see substances or structures not visible to the naked eye Magnify very small objects (not just living things!) Identify and Compare species Measure size and compare
Word Bank Eyepiece Course Adjustment Knob Diaphragm Stage Arm Support Stage Clips Base Light Support Nosepiece Fine Adjustment Knob Objective Lenses On your Microscope, Label the Parts of the Compound Light Microscope
Microscope Terms Definition: clarity; how clear the specimen appears Magnification: amount of enlargement of an image Orientation: way in which something appears to be directed Depth of Field: refers to layers, 3-D effect that is viewable by changing fine adjustment under high power Width of Field: distance across the diameter of your field of view, used to estimate the size of a specimen Micrometer: metric unit of measure –1millimeter = 1,000 micrometers Objective: degree of magnification Low = Med = High =
Steps to Storing a Microscope 1.) Turn off light and allow to sit for 5 min to cool down. 2.) Turn the stage all the way down. 3.) Return objective to low. 4.) Remove slide. Rest the stage clips on the stage. 5.) Loosely wrap and secure the electrical cord. 6.) Turn the ocular over the body tube. 7.) Cover the microscope with the jacket. 8.) Carry the microscope with two hands. 9.) Place the microscope in the closet with the ocular pointing out.
Steps to Focusing a Microscope (Know in Order!!) 1.) Turn light on and leave it on for as long as you are using the microscope. 2.) Align the slide on the stage and secure with the stage clips. 3.) Turn the ocular towards you by rotating the base, not the tube. 4.) Using the coarse adjustment, bring your specimen into view, and center it in your field. 5.) Adjust the diaphragm for the “best” lighting, not necessarily the brightest setting. 6.) Using your fine adjustment, sharpen your image (give the image definition.) 7.) Using the revolving nose piece, turn to your medium power objective. 8.) Using the coarse adjustment, bring your best image into view, center it, and turn the fine adjustment for definition. 9.) Turn the high power objective into place using the nosepiece. Using only the fine adjustment knob, fine tune your image. 10.) You may also want to change the light for a better image at this point.
What type of Microscope do I need to see….. Chloroplast (organelle) Cancer Cells Water Flea Virus Muscle Tissue Snowflakes
Measuring Using the Microscope We cannot just measure a specimen using a ruler, so we need to indirectly measure or compare the size to something we already know! Width of Field or Width of View WFLP = Width of Field Low Power WFHP = Width of Field High Power REMEMBER= Micrometer μm
Measure the WFLP Place the ruler on the stage so that it covers half of the stage opening and you can see markings GOOD 1. Make sure the ruler is centered at the center of the WF 2. What is the field of view in scanning power to the nearest in millimeters?
3. Switch to medium power and calculate the magnification. 4. You cannot measure the field for high-power, so you need to estimate…… Mag LP = WFHP Mag HP WFLP Mag LP = WFHP Mag HP WFLP
TOTAL MagEstimated WF (using ruler) Calculated WF Low Medium High Before measuring a specimen, you need a table like this….
Let’s try it #1… Ocular power = 10x Low power objective = 20x High power objective = 50x a.What is the highest magnification you could get using this microscope? b.If the diameter of the low power field is 2 mm, what is the diameter of the high power field in μm? c.If 10 cells can fit end to end in the low power field of view, how many of those cells would you see under high power? Mag LP = WFHP Mag HP WFLP Mag LP = WFHP Mag HP WFLP
Let’s try it #2… Ocular power = 10x Low power objective = 10x High power objective = 40x a.What is the approximate width of the field of view in micrometers? b.What would be the width of the field of view under high power? c.If 5 cells fit across the high power field of view, what is the appropriate size of each cell?
Let’s try it #3… Ocular power = 10x Low power objective = 20x High power objective = 40x a.If viewed under low power, what is the approximate size of the cell in micrometers? b.What would be the high power field of view? c.How many cells like the one in the picture could fit in the high power field of view? 2000 μm CELL
Drawing in the Lab Notebook Drawing # : TitleDate: Total mag: Sig: Observations: WF(under total mag) # of specimen in field Each drawing should consume ½ a page in your notebook! cell
Making a Wet Mount Carefully angle the cover-slip and slowlyplace on the specimen. Water should NOT ooze out of the cover-slip Do not drop the cover-slip on thespecimen- avoid bubbles
Whiteboard Discussion For the lowercase “a” drawing, what observations were youexpected to make? In completing the paramecium drawing, what did you findabout comparing the actual size of the specimen when youmoved from low to high power? Did the image change? Didthe specimen’s numerical width change? After creating the starfish development picture, were you ableto relate the egg’s size to that of a different specimen in adifferent power (i.e. the paramecium in high power)? When you observed the last slide, how did you decide whatpower to draw that specimen under?
What is on the test??? Microscope parts and functions How to properly store a scope How to focus an image (steps in order) How to draw a specimen Which microscope should I use? Microscopic Calculations How to work and use the scope (what objectiveto use, how to draw, basically the lab)
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