Lab 1 Activities

Magnification

Fill in the following table. You can review magnification here.

Magnification_total = Magnification_objective X Magnification_ocular

Field of View Calculation

Follow the directions below. You can review field of view here.

1. Examine a ruler under scanning magnification.
   • Measure the diameter in millimeters (mm).
   • Diameter = ______________
   • Radius = _____________
   • Calculate the field of view at this magnification = ______________
2. Examine a ruler under low magnification (10x).
   • Measure the diameter in millimeters (mm).
   • Diameter = ______________
   • Radius = _____________
   • Calculate the field of view at this magnification = ______________

3. What is the relationship in the between the magnification and field of view?
4. What is the proportion of change in field of view when doubling the magnification?

The Letter e

0. Follow this link: https://www.ncbionetwork.org/iet/microscope/
   • Click on “Explore” → Click the sample box “?” → Click “Sample Slides”
   • Click “Letter E”
1. The slide is oriented so the “e” is right side up.
   • If the image is blurry, use the focus sliders to make the image clear.
   • What do you observe about the image under the microscope?
2. Switch between scanning, low power and high power.
   • Draw the “e” at scanning, low and high magnification.

Depth of Field

Follow the instructions to explore depth of field. You can review depth of field here.

1. Examine the slide of colored threads under scanning power so the cross-point of the threads is at the center of the field (see image below).

2. Raise the magnification to the low power objective.
   • What do we notice about the threads and the focus?
   • How can we explain this observation with respect to the threads?
   • Close the diaphragm so allow a pinpoint of light through the slide. What effect does this have on the image?

Examining Cells

1. Choose a prepared slide of a Protist (Euglena, Amoeba, Paramecium).
   • View the slide under 5x, 10x, and 40x magnification.
   • How does the image change as you change magnification?

2. Prepare a wet mount of a drop of pond water and place a cover slip over the drop.
   • View the slide under 5x, 10x, and 40x magnification.
   • Do you see anything moving?

3. Prepare a slide of your own cheek cells.
   • Swab the inside of your cheek.
   • Roll the swab across a slide.
   • Drop some methylene blue onto the slide.
   • Place a coverslip over the drop (see image below).

4. View your cheek cells under 5x, 10x, and 40x magnification.
5. Document your observations by drawing the cells and by using your phone to snap an image.

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