Experiment2 Microscopy.docx

The use of 1 Microscopes Name: Khulud Abdulaziz Nazer ID: U00045236 September 23 2014 General biology lab Section: 13 T Instructor: Tasneem Obaid Introduction: Microscopes are instruments used to enlarge objects that are too small to be seen by one’s eyes. Microscopy is the science of the examination of small objects using microscopes. Technically we have two types of microscopes, the optical microscope which was first invented in late 1500s. It
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   The use of 1 Microscopes  Name: Khulud Abdulaziz Nazer  ID: U00045236 September 23 2014 General biology lab Section: 13 T Instructor: Tasneem Obaid   Introduction : Microscopes are instruments used to enlarge objects that are too small to  be seen by one’s eyes.  Microscopy is the science of the examination of small objects using microscopes. Technically we have two types of microscopes, the optical microscope which was first invented in late 1500s. It uses light and glass lenses (objectives) to magnify the image of an object up to 4X, 10X, 40X and a 100X. The second type is the electron microscope which was developed at early 1900s, it uses an electron beam in the place of light and electromagnets in the place of objectives to allow a much higher resolution up to two million times. In this experiment we will be using the optical microscope and not the electron microscope to examine specimens, as it is available in almost all the laboratories. In addition, the costs of the optical microscope is too low compared to that of the electron microscope. Moreover, the optical microscope can be stored in normal room temperature and pressure not requiring a vacuum as the electron one does.  Materials : Compound light microscope and stereomicroscope. Prepared dry mount of the letter “e”  . A plug. Method :   First of all, we used a compound light microscope to assess the letter “e”.  We followed the following procedure; A slide of dry mount of letter “e” was previously prepared. The letter was first observed by the naked eye and a sketch of it was made. We made sure that the compound light microscope cable was in the electricity plug and the power of the microscope was on. As for the light of the microscope. The 4X objective was chosen by spinning the nosepiece. We altered the clips by lying the specimen slide down on the stage. By using the coarse adjustment knob, we moved the stage vertically to focus the image of the letter “e”. And by using the fine adjustment knob, we moved it horizontally to sharpen the image. The image was observed and the sketch was made too. The same steps were repeated to examine the letter “e” with the same compound light microscope with 10X and 40X objective lenses. Sketches of each were drawn. When finished, 10X objective was back o its place, stage was at it’s lowest level and the power was switched off. It was then stored away by us. Then a stereomicroscope was used to assess the letter “e” as well.  The stereomicroscope was turned on. We placed the specimen slide on the stage of the microscope. We set the scope on 4X objective. The slide was made at the middle of the stage by altering the fine adjustment knob. The slide was moved by the coarse adjustment knob until the image of the letter “e” was focused.  The image was therefore observed and a sketch was made.  Results : The sketch of the letter “e” at each objective differs depending on the  power of the objectives. The higher the power the more the detailed the image of the letter “e” is shown. However, the less the power of the objectives the less the magnification takes place. Hence, less detailed image. The table below shows our sketches with the different objectives of both microscopes. The table above shows the results obtained by us after we observed the letter “e” under different magnifications on both the compound light microscope and the stereomicroscopes. First sketch-letter e (naked eye)- shows the image of the letter when seen by the naked eye. The second sketch- letter e (4x lens)- from the left shows how the letter becomes more detailed when used under the 4X objective of the compound light microscope. The third sketch- letter e (10x lens)- however shows how a  bigger version of approximately half of the letter was seen with very small details of the lines of the letter using the compound light microscope. The fourth sketch- letter e (40x lens)- is the clearest of all showing the tiniest threads of the letter when used under the compound light microscope. Finally, the last sketch on the right- letter e (stereomicroscopes)- shows how the image looks clearer when used under the stereoscopes than that of the naked eye. Discussion : The main objective of this experiment is to show how the use of any type of microscopes magnify and clarify the small images that are required to  be accurately seen. Also, the use of different powers of the objective lenses and the results each magnification power shows after the test. It is clearly shown that the objectives were supported by the results obtained from the above experiment. Most of the results from previously worked experiments from other students showed the same outcomes, with very slight differences in the way they drew their sketches. There is a probability that the results are not very accurate because each experiment was done only once with the


Jul 23, 2017
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