Introduction to the Light Microscrope LAB

Parts of a Microscope: Familiarize yourself with the parts of the microscope. Go through the microscope and quiz your partner on the name of the parts.

1. Magnification:

Complete the following chart in your lab book:

Type of Lens / Individual Magnification / (Multiply eyepiece X objective lens) / Total Magnification
Eyepiece/Ocular lens / xxxxxxxxxxxxxxxxxxxx
scanning/low power objective lens / x E =
medium power objective lens / x E =
high power objective lens / x E =

2. Diaphragm: Locate the diaphragm under the stage. Turn on the microscope and adjust the diagrams while looking through the eyepiece. Did you find it? If not, signal your teacher for help. In your notebook, explain what it does.

3. Eyepiece: Look into the eyepiece, twist it left and right. Notice the line inside that moves as you twist.

(Some microscopes do not have this, see if you can find one that does in the room). In your notebook, explain what this line does and what the line is used for.

4. Viewing an Image: Place the slide of the "letter e" on the stage so that the letter is over the hole and is right side up. (Make sure the specimen is centered).

  1. Use the scanning objective to view the letter and use the coarse knob to focus. In your notebook, draw the letter “e” under as you see it. Drawings should be drawn to scale

Note the orientation of the “e” in the viewing field (is it upside down or right side up?

Have your partner push the slide to the left while you view it through the lens. Which direction does the “e” appear to move?

  1. Repeat on the medium power objective. In your notebook, draw the letter “e” under as you see it.
  1. Finally, switch to high power. Remember at this point, you should only use the FINE adjustment knob. In your notebook, draw the letter “e” under as you see it.

SCANNING/LOW
/ MEDIUM
/ HIGH

5. Viewing Prepared Slides: Choose 1 specimens from the box of "common things". In your Notebook, sketch your specimens under Scanning/Low and Medium power. You may practice focusing with the high power, but you do not need to sketch it. Label your specimen from the name written on the slide.

Specimen 1 ______
Scanning/Low Power
Medium Power

6. Creating and Viewing a Wet Mount Slide. Obtain a slide and coverslip.

a. Take a drop of pond water and pipette it onto the center of your slide. At an angle, lower the coverslip on top of your drop of water. Sketch what this procedure looks like in your notebook.

b. Beginning with the scanning/low power objective, scan through your drop of pond water to fins any organisms. When you think you found something, turn the revolving nosepiece to medium power to get a closer view. Repeat until you found an organism to sketch. Then, turn your objective to the high power objective lens. In your notebook, sketch your specimen. Label your specimen “Pond Water Organism”.

Specimen ______
High Power

Remove the slide, wipe it down, and dry it and place it back in the bin.

7. Turn off the microscope and wind up the wire so it resembles its original position. Place the low power objective in place and lower the body tube. Cover the scope with the dust cover. Place the scope back in its original space.