LabLearner—The Science of Learning
LabLearner—The Science of Learning

Teacher Portal:

Microscopic Explorations

Investigation 3 – Lab

 

 

 

 

 

 

 

Back to Investigation 3

ASK WHY

Microscopes are one of the most important scientific instruments developed. In fact, in the medical field, microscopes are largely responsible for making modern medicine “modern”!

BRANCH OUT

In LabLearner we use compound light microscopes. These are very widely used in both research and clinical and industrial applications. However, there are many additional types of microscopes that are used for various purposes. Among the most useful in research is the electron microscope. While light microscopes have a maximum magnification of about 1,000X, electron microscopes have magnifications of around 300,000X with even better resolution than a light microscope. Whereas light microscopes may be able to see organelles within cells, like the nucleus and even mitochondria, electron microscopes can actually see individual atoms!

BE PREPARED

Group materials:
  • 1 water bottle
  • 100 ml of blue water
Pair materials:
  • 1 microscope
Individual materials: 
  • 1 coverslip
  • 1 paper towel
  • 1 rounded end toothpick
  • 1 blank slide
  • 1 plastic dropper
  • 1 Scientist Data Record

Teacher Preparation

1. If the microscopes do not have a blue filter, prepare 500 ml of blue water. Add 1 drop of blue food coloring per 100 ml of water.

2. Provide each student group with 100 ml of blue-colored water.

3. Divide the class into pairs. Assign two to three student pairs to a table. Each student pair will receive one microscope.

GET FOCUSED

During this Investigation, students will conduct two Trials. Trial 1 has been designed to provide students with an opportunity to learn a new procedure from the Procedural Toolbox: Wet Mount Slide Preparation. In this Trial, students will obtain a sample of their cheek cells and prepare the cells for microscopic analysis.

  • What is a wet mount slide?

  • What is the procedure for making a wet mount of cheek cells?

In Trial 2, students will observe their cheek cells specimens using the compound microscope. As students study their specimens they should be aware of the differences in the magnification, resolution, and field of view afforded with each objective.

  • What information about the structure and function of cheek cells can be learned from microscopic analysis?

_____________________________________________

Trial 1

1. Direct each student to obtain the following necessary materials from the distribution point: one (1) glass slide, one (1) coverslip, one (1) rounded end toothpick, one (1) plastic dropper, and one (1) paper towel.

Note: During the experiments, the instructor may choose from the following methods: (1) guide the class step-by-step through the instructions, (2) permit student pairs/groups to work together on their own, or (3) combine instructor guidance and independent work.

Note: If time in the lab is a concern, one student in each pair/group should be responsible for recording the required data in the Scientist Data Record. The remaining students can transfer the data into their records at the end of the experiment.

KEYS: TRIAL 1

Trial 2

During this trial, students will be prompted to use the blue filter or blue water when viewing their cells. In previous investigations, students viewed specimens that were innately colored (crossed fibers and letter “e” slides) or stained (cork slide). The cheek cells that students will view in this trial are unstained and therefore are clear in color. This may make it difficult for students to find the cells on the slide. The use of the blue filter or blue water provides some contrast between the cells and the water, thus aiding students in finding the cells on the slide.

NOTE: If using Junior Cadet microscopes, students will use the blue filter during this trial. If using microscopes that do not have the blue filter or additional glass piece that changes the color of the light source, students will use the colored water. The blue color in the water will facilitate the identification of the cells.

Note: Upon completion of the experiment, permit enough time to clean up the lab and return the materials and equipment to their assigned locations. Dispose of rounded toothpicks in the trash and the glass materials in areas designated for sharp materials.

KEYS: TRIAL 2

CLEAN UP

Let students know your expectations for clean-up. Ask them to clean up.