The foundation of Biology 156 starts with the first lab. The knowledge and use of the microscope. Without this complex tool for the time of its invention, the scientific world might not have advanced in the manner it has. For, a great view into our microscopic world, the microscope is used on these basic concepts.One should grab the microscope by its Arm, and support it under its base. Place it on a level solid table, having the arm towards its user. Using the larger knob for course movement, adjust the microscope’s body tube to its furthest resting point from the stage. Adjust the nosepiece so its low-power objective lens is over top the hole in the stage and it clicks into place. The diaphragm can now be moved as one looks through the eyepiece putting the circle of light centered to the hole in the stage. Now it’s ready for viewing. Place your slide on the stage, centering up the specimen. Place stage clips on slide when in place. Looking at the stage from the side use the course adjusting knob move the low-power objective lens towards the stage almost kissing the slide. Now looking through the eye piece, adjust the course knob until specimen come into focus. From there one can move to higher power objective lens and then use the fine adjusting knob to bring the specimen into focus. Welcome to our microscopic world.
The compound microscope has many moving parts that can mean a specimen is magnified poorly or correctly. To start off making sure the slide is clear of debris and dust when placed on its platform or the stage, is a good place to start.
The stage should be level and moved to it farthest resting point away from the body tube. The stage it’s self is static and by using the coarse adjusting knob the body tube can be moved up and down.
The coarse adjusting knob is used to move the body tube and the lens in a fast manner. Twisting the coarse knob is used during initial set up and during low magnification. During initial set up the course adjusting knob will bring the objective lens down to the slide almost touching. Once the microscope is in this position the ocular lens and iris will be adjusted.
The Iris is a hole in the stage. It lets light come up through the stage from the light source under the stage. The amount of light is adjusted for clarity by the diaphragm, depending on your slide and specimen. While viewing more light might be needed, and the diaphragm is rotated allowing more or less light through the iris.
The Oculars are for viewing your slide. They should be look viewed from a distance of about 3 inches. When first looking through the oculars the will need to be adjusted so one complete circle is formed while using both eyes.
The Objective lenses are closest to your slide. These lens come in different magnification depending on you microscope. Your common magnifications are 100X, 40X, 10X, and 4X. The 4 power lens is used to start off at the beginning, so that you can focus you slide from a general view and then once in focus change magnifications. During focus of the 4X lens you can use the course adjusting knob. When magnification changes to 10X or greater you need to use the fine adjusting knob to focus. During your observation of just 4X you will have magnified the slide to that of the first microscopes, being use by their inventors. Now there is Dissection, Scanning Electron (SEM), and Transmission Electron microscopes (TEM) that are bring the microscopic world to us in 3-D.
The Objective lenses are closest to your slide. These lens come in different magnification depending on you microscope. Your common magnifications are 100X, 40X, 10X, and 4X. The 4 power lens is used to start off at the beginning, so that you can focus you slide from a general view and then once in focus change magnifications. During focus of the 4X lens you can use the course adjusting knob. When magnification changes to 10X or greater you need to use the fine adjusting knob to focus. During your observation of just 4X you will have magnified the slide to that of the first microscopes, being use by their inventors. Now there is Dissection, Scanning Electron (SEM), and Transmission Electron microscopes (TEM) that are bring the microscopic world to us in 3-D.
In the late 1500’s the credit for the first compound microscope was given to the Janssen Family of Middleburg, Holland. Their first compound microscope was simply a tube with lenses at each end. Over the next century Robert Hooke and Anton van Leeuwenhoek took the quality and magnification to new levels. Hooke’s publication Micrographia were the word “cell” was started, it was use to describe the plant tissue from an oak tree. Leeuwenhoek only improved on the microscope, being an inventor and building the best of his time period. Leeuwenhoek also is known for describing the first bacteria off of teeth and describing protozoan out of ponds. After that the microscope continued to improve and change and allow scientists to view deeper and deeper into the microscopic world. With the basic knowledge of the microscope one can start to explore the microscopic world that lives around us. While doing so, think of the excitement that the founding fathers of microscopy must have felt while seeing objects magnified for the first time.
Cheek cells from Web microscope. Using 10X, and 40X objective lenes.
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