Activity for Biotechniques: Measuring Pollen Size Using a Razor Blade Scores Scale and Microscope

One technique used to determine the size of objects under the microscope is to compare it to an external standard as a razor score scale. This however, is made possible only on straight body tube, monocular microscopes.

OBJECTIVES:
1. To describe pollen grains seen under the microscope.
2. To determine how many times a pollen is magnified under the HPO of the microscope.
3. To illustrate pollen grains as seen under the HPO of the microscope.
4. To measure the size of pollen grains under the microscope using the razor blade scores scale.

MATERIALS:
glass slides
compound microscope
dissecting needle
razor blade scores scale
flowers with pollen grains

PROCEDURE:
1. Dust off some pollen on the surface of the glass slide.

2. Observe under the LPO of the microscope.

Q1. Describe the pollen grains.

3. Then shift to the HPO.
Q2. How many times have these pollen grains been magnified?
Q3. Draw 2 or 3 pollen grains as seen under the HPO. Indicate the magnification.

4. Ussing the dissecting needle, transfer dew pollen grains directly over the razor glade scores scale.

5. Observe the pollen grains under the LPO.
Q4. Describe what you have observed.
Q5. Make an estimated of the size of the specific pollen you are observing.
Q6. If four pollen grains can fit in one scale, What is its estimated size.

Activity for Biotechniques: Making a Razor Blade Scores Scale

In this activity, you will make a scale to measure sizes of objects seen under the microscope.

OBJECTIVES:
1. To use the HPO of the microscope in checking score made by razor blades on TP.
2. To describe the steps in making a razor blade score scale.

MATERIALS:
glass slides
Rubber band transparent tape
razor blades transparency sheet (TP)
Cutting mat or chopping board
scissors / cutter

PROCEDURE
1. Bundle 5 razor blades with rubber band.
2. Place the TP sheet on a cutting mat or chopping board to make scores on the TP sheet with one stroke of the bundle razor blades.
3. Cut out the scored TP sheet about the size of a cover slip.
4. Tape on the sides the scored TP sheet to a glass slide.
5. View under the LPO of the microscope.
6. Are the four spaces even or equidistant to one another? if not repeat 2-4 until you have an equidistant scored sheet.
7. You may have a razor blade scores scale. You will scale in activity.