Online Lab 1- Microscope Simulator

The microscope is an important tool in biology because it allows scientists to magnify cells and small organisms, making it possible to see them close up. Microscopes have made it possible for scientists to discover new organisms, study cell and tissue structure, and fight disease. Microscopes are also important in the medical field. Years ago , while I was working at a public health clinic, we would use a microscope to find out if patients had certain fungal or bacterial infections. Often we would be able to treat patients right away rather than sending specimens to a lab. Obviously, we would not have been able to provide as high a quality of care without a microscope.

I was surprised to learn that the use of magnification and lenses can be traced as far back as ancient Egypt! The credit for the first actual microscope goes to Zacharias Janssen an eyeglass maker from Holland, around 1595. Because of Zacharias' age, some people think his father Hans might actually have invented it (I am choosing to believe it was the whippersnapper myself, I love it when young people do great things). The Janssen's microscopes were simple by today's standards, tubes with lenses at both ends. Depending on the diaphragm openings, magnification ranged from 3x to 9x. English chemist, Robert Hooke later improved on the early compound microscope and is responsible for coining the word "cell." He also wrote Micrographia which would influence inventor Anton Van Leeuwenhoek. Leeuwenhoek's scopes were simple but considered the best in his day. He was also the first person known to describe organisms like bacteria and protozoans.

This image was taken from http://www.southwestschools.org/jsfaculty/Microscopes/history.html

and is a "tube microscope" with a lens at each end.

The Janssens' microscopes were also important because of the addition of a second lens. the second lens allows for greater magnification by magnifying the image from the first lens. Compound light microscopes today reach magnification levels up to 1000x. The first electron microscope, built in 1931 by Max Knoll and Ernst Ruska, brings magnification even further, 50,000. There are two kinds of electron microscopes, scanning, SEM and transmission, TEM. I had never seen one so below is a picture I found at rsic.puchd.ac.in/em.html

Another kind of microscope is the dissection microscope, used in dissecting specimens.

I got the image above at http://www.hometrainingtools.com/misc/compound%20parts.jpg I thought it was helpful in showing the parts of a microscope.

So, all of this is good to know, but can I actually operate a microscope? Well, I thought so but admittedly, it has been awhile! I very much appreciated the video for the microscope simulator. It is important to prepare the microscope before trying to view a specimen. The condenser knob should be turned all the way up and the rheostat adjusted to ten. the condenser knob is used to adjust the height of the condenser. The iris helps to adjust the angle of the light coming from the top of the condenser. I learned, by using the simulator, that the iris is important in getting a good quality image. The objective is basically the microscope and contains lenses. The nose piece we used in the simulator revolved and had different levels starting at 4x and going all the way up to 100x. The website with the history of the microscope explained magnification as the combination of the eyepiece and the objective. However there was no magnification given for the oculars (eyepiece) on the simulator, so I just used the 4ox objective to get my image. Before beginning, the revolving nose piece should be set at the lowest objective, 4x. It is also important to adjust the oculars so they are both even. Additional adjustments may be necessary before viewing the image. The slide is placed on the stage (the platform that holds the slide) and the stage clip(s) hold the slide in place. The coarse adjuster knob should be adjusted away from you, raising the platform up towards the objective. You are now ready to view the image. Below is the image from the website.

I started by moving the coarse adjuster knob to bring the specimen into view. I then adjusted the fine focus knob and the iris to get a clearer image. The simulator had XY controls that moved the specimen back and forth and and front to back. I then rotated the objectives to get a greater magnification. each time I changed the objective I would adjust the fine focus and iris. I did this of course, while looking through the oculars.

Care and clean up is also important. Slides and lenses should be cleaned with lens paper. Kleenex or paper towels can scratch and should not be used. It is also important to turn the microscope off. A few times the microscope was left on at the clinic and the bulb burned out, not good.

This lab was helpful to me. I would have embarrassed myself if I had tried to use a microscope on my own in class. I noticed I would forget steps when I used the simulator and had to review what I had done. I now have a much better understanding of how to use a microscope.