First of all, I really enjoyed doing the microscope simulator. I would of loved to look at many other things. Anyway, here is my write-up.
The first microscope was founded about the year 1590 by Hans and Zacharius Janssen*. Hans was a Dutch e
yeglass maker, who passed all of his findings to his son who later took credit for the microscope. On the left here, is a picture of their first microscope. In the years 1635-1703, Robert Hooke, who was an English chemist, made some alterations to the microscope. Then, around 1632-1723, Anton van Leeuwenhoek was the first person to describe bacteria and protozoans. Now, there is 4 different types of microscopes.
yeglass maker, who passed all of his findings to his son who later took credit for the microscope. On the left here, is a picture of their first microscope. In the years 1635-1703, Robert Hooke, who was an English chemist, made some alterations to the microscope. Then, around 1632-1723, Anton van Leeuwenhoek was the first person to describe bacteria and protozoans. Now, there is 4 different types of microscopes. 
1. Compound, which is the most commonly used, has a 2D picture and high magnification but low resolution. Here is a picuture at right.
2. Dissection which has 3D picture, but cannot see individual cells because of low magnification.
3. Scanning Electron Microscope (SEM), uses electron illumination with 3D image, has high magnification and high resolution and pictures are in black and white.
4. Transmission Electron Microscope (TEM), uses electron illumination, with 2D image, uses thin slices of specimen, while electron beams pass through the specimen. Has high magnification and high resolution.
Using a microscope isn't as complicated as it looks, once you learn the different parts and how they work. To the right your will see how it basically works. First of all, turn the power on, select slide, while looking at the microscope, place slide on the stage and secure with stage clip. The stage moves up and down. Initial movement is done not looking through oculars. You may need to use XY controls to make sure specimen is above light source, also done by looking at microscope. Before looking into oculars, make sure objective 4X is in place, then turn course adjustment knob, to place stage all the up. Make sure the iris is closed so you don't blind yourself at first look. Then, as you look into oculars adjust them to fit your eyes, you should see one circle while looking through it. Using the fine adjustment knob, turn slowly, to bring specimen into focus. This knob is actually adjusting the stage in very small movements. You can then change the objectives, by turning nosepiece, and use fine adjustment to bring back into focus and open the iris some more to allow more light on your specimen when needed. Doing the fine focusing is best done looking through microscope. While changing objectives can be done looking at the microscope.
Here is an onion root image. Internal organelles have been stained to stand out and show some detail. This image is seen through a 40X objective. Total magnification, then being 400X.
In conclusion, the importance of the microscope is to study different bacteria, protozoa and the way things work inside of cells and so forth. Without the microscope we wouldn't have any slight understanding of the smallest things that are naked to the human eye. While studying these small "things" we can understand a little about cells, DNA, bacteria, protozoa and etc. I am glad that the men mentioned before, Janssen family, Robert Hooke and Anton van Leeuwenhoek, had a vision to see things that couldn't be seen. They led us to where we are now in technology and understanding.
*All history info taken from following website:
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