The compound light microscope. 1. The Compound light microscope has two lenses. A. Ocular lens - the eyepiece B. Objective lens --the lens closest to the specimen. 2. The lenses have two functions Magnify-- to increase the size Resolution--make the object clear and have detail.

MAGNIFICATION Black widow spider claw 3. The ocular lens & objective lens have a magnification on them identified by an X. 5. A 20x-- means the lens magnifies 20 times the normal size. Low power lens has a 10x High power lens has a 40x. To find total magnification multiply the ocular lens by the objective lens. Ocular is 4x and objective is 10x = _________ Ocular is 10x and objective lens is 40x = _________ Black widow spider claw 500x

1 6 2 7 8 3 9 4 10 5 Base

Eyepiece-- what you look through. Arm-used to carry microscope Course focus knob--brings specimen into focus. Fine focus knob--make small adjustments in focus. Base--used to carry microscope Objective lens--magnifies specimen Stage--where you put the slide Stage Clips--they hold the slide in place. Diaphragm--adjusts the amount of light going to slide. Light/mirror--gives light to specimen to see easier.

How to use the microscope 6. Always carry the microscope with one hand on the Arm and one hand on the Base. 7. Carry it close to your body. 8. Always start and end with the Low Power objective lens!

9. Place the slide on the microscope stage, with the specimen directly over the center of the glass circle on the stage (directly over the light). 10. If, and ONLY if, you are on LOW POWER, lower the objective lens to the lowest point. 11. Focus using first the coarse knob, then the fine focus knob. 12. Adjust the Diaphragm as you look through the Eyepiece. Sometimes you will see that MORE detail is visible when you allow in LESS light! 

13. Once you have found the specimen on Low Power (100x), center it, then switch to the High objective lens. Now only use the fine focus knobs. 14. If you don’t center the specimen you will lose it when you switch to High Power.

15. Once you have it on High Power remember that you only use the fine focus knob! “Caution, do not remove the slide when it is on High Power.” -- The High Power Objective (430x) is very close to the slide.

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?

Drawing the specimen Each drawing must be done in pencil and must include clear proper labels. Write the specimen name as written on the slide label, also include the magnification (100x or 430x). Each drawing must have the following labeled. Cell membrane Nucleus Chromatin--The DNA inside the nucleus. Usually appears as a dark mass.

Putting the microscope away. 18. Make sure the microscope is on low power. 19. Unplug the microscope and wrap the cord around the base. 20. Cover the microscope and with one hand on the arm and the other on the base, carry the microscope to the table.

100x 40x 400x

Kosher salt 75 X

Artery