The Microscope
The Parts of a Microscope
Ocular Lens Body Tube Nose Piece Arm Objective Lenses Stage Stage Clips Coarse Adj. Diaphragm Fine Adjustment Light Source Base Skip to Magnification Section
Body Tube The body tube holds the objective lenses and the ocular lens at the proper distance Diagram
Nose Piece The Nose Piece holds the objective lenses and can be turned to increase the magnification Diagram
Objective Lenses The Objective Lenses increase magnification (usually from 10x to 40x) Diagram
Stage Clips These 2 clips hold the slide/specimen in place on the stage. Diagram
Diaphragm The Diaphragm controls the amount of light on the slide/specimen Turn to let more light in or to make dimmer. Diagram
Light Source Projects light upwards through the diaphragm, the specimen and the lenses Some have lights, others have mirrors where you must move the mirror to reflect light Diagram
Ocular Lens/Eyepiece Magnifies the specimen image Diagram
Arm Used to support the microscope when carried. Holds the body tube, nose piece and objective lenses Diagram
Stage Supports the slide/specimen Diagram
Coarse Adjustment Knob Moves the stage up and down (quickly) for focusing your image Diagram
Fine Adjustment Knob This knob moves the stage SLIGHTLY to sharpen the image Diagram
Base Supports the microscope Diagram
Magnification
Fill in the table on your worksheet. What’s my power? To calculate the power of magnification, multiply the power of the ocular lens by the power of the objective. What are the powers of magnification for each of the objectives we have on our microscopes? Fill in the table on your worksheet.
Comparing Powers of Magnification We can see better details with higher the powers of magnification, but we cannot see as much of the image. Which of these images would be viewed at a higher power of magnification?
Caring for a Microscope Clean only with a soft cloth/tissue Make sure it’s on a flat surface Don’t bang it Carry it with 2 HANDS…one on the arm and the other on the base
Carry a Microscope Correctly
Using a Microscope Start on the lowest magnification Don’t use the coarse adjustment knob on high magnification…you’ll break the slide!!! Place slide on stage and lock clips Adjust light source (if it’s a mirror…don’t stand in front of it!) Use fine adjustment to focus
Let’s give it a try ... 1 – Turn on the microscope and then rotate the nosepiece to click the red-banded objective into place. 2 – Place a slide on the stage and secure it using the stage clips. Use the coarse adjustment knob (large knob) to get it the image into view and then use the fine adjustment knob (small knob) to make it clearer. 3 – Once you have the image in view, rotate the nosepiece to view it under different powers. Draw what you see on your worksheet! Be careful with the largest objective! Sometimes there is not enough room and you will not be able to use it! 4 – When you are done, turn off the microscope and clean up or put away the slides you used.
You do not need to use the stage clips when viewing wet-mount slides! How to make a 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. 4 - Slowly lower the cover slip on top of the drop. Cover Slip Lower slowly VIDEO 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.
References http://www.cerebromente.org.br/n17/history/neurons1_i.htm Google Images http://science.howstuffworks.com/light-microscope1.htm
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