Science Discovery

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Science Discovery Objectives

list and describe the three aspects of science discovery?
explain the basics of microscope use (microscopy), including history, magnification, and the use of stains?
distinguish between the four major types of tissues?

There is usually some aspect of science discovery for everyone. Here is a brief introduction to the process.

The process of science discovery includes exploration, description, and explanation.

Exploration

Investigating new (to you) natural phenomena. Can be a new location, or a new way of viewing familiar surroundings.

Description

Providing accurate details about a natural phenomenon. Can include a portrait of an organism, or the steps of a process like a bud opening on a tree.

Explanation

Providing information on how or why something happens. Can be a simple cause and effect, or a much more detailed process of steps with complex variables.

In this course you will explore, describe, and explain, as well as learn from others who have gained knowledge through science discovery.

This is a lab course. When you think of a biology lab, what is the main piece of equipment you expect to see?

Whenever there is a photo of paper ephemera from old books and magazines, like this picture, that is a visual cue to back up the verbal cue that you are accessing past experiences and knowledge.

The earliest optical or “light” microscopes date back to the seventeenth century, magnifying specimens beyond the range of normal human vision. Early magnification was approximately 10x, or ten times the unaided eye,

Now microscopes that shine light through specimens can magnify over 1500x and electron microscopes developed in the 20th century magnify 200,000x. Most of the research topics discussed in this course requiring microscopic examination, or “microscopy,” would use an optical “light” microscope.

The photos on the right are different high magnification views of a bee.

One consideration in looking at microscope images throughout this course is that you are typically just looking at a small piece of a larger specimen.

Total magnification is the magnification of the eyepiece times (x) the magnification of the objective being used.

A bright light shines through a thin tissue of cells and finely ground glasses magnify the image. Both the eye pieces and specialized lenses called “objectives” magnify. From this image, if you have a 10x eye piece and a 10x objective, what is the total magnification?

answer: 100x

Here are a few basics on glass lenses and light sources in microscopes, as well as staining of animal tissues in microscope slide preparation. The slides used come from a variety of animals; many have cells similar to humans.

You can select the closed captioning “cc” option if you would like to see the text.

Antique microscope slides were frequently prepared with chemicals that are now known carcinogens (cancer-causing agents), that are no longer used. Unfortunately the high quality coloring and contrast produced by these stains has not been fully replicated.

This video shows examples of dramatically different stains from an antique slide collection.

Stains can turn clear cells that are difficult to read into powerful sources of information. Using a medical example, women get regular pap smears to detect possible abnormal growth in the cells lining the cervix. These cells are colorless under bright light until stain is added.

Normal Cells 200x

The normally colorless cells are staining shades of pink and purple, which indicates different stages of the cells. The pink were on the surface being sloughed off, the purple were a bit deeper in the lining tissue. The are all about the same size with similar size and shape nuclei (dark purple dots).

Abnormal Cells 200x

At first this may look similar, but look at the different colors and sizes of the nuclei (small circles) within the cells. They are especially different in the bluer cells that are from deeper in the cervical lining. This indicates abnormal growth and could not be easily detected without stains.

This video introduces cells and tissues (groups of cells) that are visible with a microscope. This examination will continue on the next few webpages.

The next section goes into further detail on cellular structures.

Check your knowledge. Can you:

list and describe the three aspects of science discovery?
explain the basics of microscope use (microscopy), including history, magnification, and the use of stains?
distinguish between the four major types of tissues?

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Science Discovery