Using a Compound Light Microscope - Report Example

of teacher # The Microscope Introduction Microscopes have played important role and are now being used to have been used in all science research advancement. Progress and advancement in the use of microscope and its technology has open ways for more in-depth understanding of science and research. Thus, new discoveries are now possible using microscope technology (Wood 100). Microscopes With the use of microscope, it is now possible to know more closely about cells. This was not possible without microscopes as we are unable to see, understand and know how life works. Microscope is an instrument which helps to see objects which are unable to see with naked eyes as they are too small. Importance of Microscopes With the invention of the microscope, a whole new dimension is opened to know and understand more about science. Thus, microscope technology has made advancement in science. Through the use of microscopes, it has become easy to discover and learn about the microorganisms, structure of cells and know more about animals, fungi and plants more closely. Moreover, microscopes are also being used to diagnose illness in hospitals all over the world. With the advancement in microscope technology, microscopes’ use has moved far beyond as visible light refracting lenses. Now, electrons, infrared rays and x-rays are used to detect the smallest structures to diagnose and treat the illness. Furthermore, electron microscopes are used to obtain information about viruses. Types of Microscope Basically, microscopes are of two types i.e., Light Microscope and Electron Microscope. Light Microscopes The light microscope is a well used research tool in biology because it helps to detect small objects through visible light. This instrument is expensive depending upon its versatility and quality. Moreover, light microscopes are used widely to look more closely at cells in a tissue; however, its visibility is limited to see objects less than 0.2 micrometers. Electron Microscopes Electron microscopes are used to see much smaller objects which are inside cells. Moreover, the thinnest of cell walls are also seen which shows how diffusion and active uptake is used which transfer molecules in a cell wall. Electron microscopes are found and used in all routine laboratory procedures and biological laboratories. Moreover, its use is now increased in most researches. Materials and Methods The material required for the lab include Compound microscope Euglena Glass slides Paramecium Cover slips Human Blood cells Eye dropper Beaker of water Pond Water lens The letter "e" cut from newsprint Scissors Method 1. Hold the compound microscope utilizing both hands in a way that one of the hands is kept under the arm of the microscope while the other one is rested below the base. 2. One microscope will be used by each by each group. 3. Closely examine the different parts of the microscope. 4. Plug the microscope’s electrical cord and then turn it on. 5. The condenser needs to be positioned as high as it may go by turning the adjustment provided named sub stage adjustment. It helps in the exposure of the microscope to bright light. 6. The lever beneath the condenser is used to adjust iris. 7. While viewing through the ocular lens, a circular field evenly illuminated similar to full moon can be seen. 8. The slide is then placed over the stage to view at low power. 9. The fine adjustment is used to have a sharp focused image. 10. The amount of light is adjusted using the iris diaphragm while its intensity is controlled by condenser. 11. Prepare wet mount slides. 12. Then each object considered as part of experiment to be viewed is viewed under the microscope and the required observations are taken. 13. After the whole experiment, remove the slides and wash them with water. Microscope Theory As mentioned afore, Microscope is an optical instrument that makes use of a single lens or a combination of lenses to generate enlarged images of objects that can’t be seen by naked eye. Microscopes may be categorized as electron microscopes (e.g. SEM, TEM). Light microscopes and scanning probe microscopes.  ` Light Microscope The light properties are used by light microscopes to magnify images. It is the simplest type of microscope and categorized into Simple microscope and Compound microscope.  Simple Microscope This microscope makes use of light through a single lens. Mostly they are planoconvex or double convex lenses. Compound microscope   In the compound microscope used two lenses or lens systems. One lens magnifies the image of an object which is then again magnified by the second microscope. The compound microscope is composed of two lenses one is called the eye piece whole the other one is known as objective. The total magnification is the product of both magnifications. Electron Microscope The electron microscope uses the electronic beam to view small objects of about nanometer to micrometer in size. They were developed as the light microscopes were limited in their magnification to 500 xs to 1000x. They may be transmission electron microscope or Scanning electron microscope. Regardless of type they work in a similar way as the light microscopes. An electron beam from the electron gun is utilized to magnify the specimen’s image (Wanamaker). Care and use of Microscope Since microscopes are expensive instruments they need to be handled with care. Both hands should be used while holding the microscope. The stage should be kept up and the smallest objective lens to be kept in front. The slide should be placed in the centre of stage along with stage clips. The slide should be focused while keeping an eye on the eye piece. The lenses should be cleaned using lens paper. Lenses should not be touched with fingers. A dust jacket should be put over the microscope and it should be kept in a dry place. Moreover the lower resolution should be used while viewing a specimen. Parts of Microscope The parts of a compound microscope and their functions are mentioned below. Eyepiece Lens:  It is the lens of 10x or 15x power and provides the final image.  Tube:  Links the eye piece and the objective lenses. Arm:  Provides supports to the tube and links it to the base Base:  It is the bottom and is used to support other parts. Illuminator: Instead if a mirror a steady source of light is utilized of 110 Volts. Stage:  Provides the platform to set slides using stage clips. Revolving Nosepiece or Turret: It carries two to three lenses and may be rotated to change power. Objective Lenses:  The objective lenses of varying powers provide the initial image for the eye piece. Rack Stop: Provides the adjustment for keeping the objective and the slides apart. Condenser Lens: It focuses light to the slide and are best utilized at highest powers.   Diaphragm or Iris:  A rotating disc is preset in many microscopes just beneath the stage. The diaphragm has contains holes of various sizes to provide variance in the cone size and intensity. Focusing the microscope In order to focus the microscope smallest power objective should be used initially and while viewing through side the lens may be cranked down as close to the slide as possible without colliding with it. Keeping an eye on the eye piece and keeping an upward focus adjust the microscope until a sharp image is obtained. The process may be repeated until a sharp image is obtained. Once the sharpness is attained the objective may be changed to high power as required by the experiment using the focus knob. Image Orientation Since the compound microscope provides an inverted image, the orientation must be set using a letter E cut from a newspaper. The slides may be fixed afterwards to get the right image (Morton, Perry, and Perry 300). Size estimation The size of objects under observation varies from 80- 350 microns Wet mount slide Preparation First of all the slides are needed to be cleaned using Kim-wipe tissues and water. Then a drop of water is placed within the centre of the slide. Using tweezers the letter e is kept upside down over the water drop and a cover slip is then placed over this letter e in a gentle manner by touching the edge of water drop and lowering the cover slip over the letter e. A hand lens may be used to observe the prepared wet mount slide. Then the slide is placed on the microscope’s stage to be examined under the microscope. The clips are adjusted and using the low power lens and making a use of coarse adjustment knob initially while fine adjustment knob afterwards for adjusting the image. Then the objective lenses are changed and the slide is examined (Armstrong). Observations i. "e". The examination of letter e under the microscope resulted in various observations like an initial inverted image was observed then in an attempt to draw it right side up resulted in an inverted image. When it was tried to move the slide towards left the image moved to the right. Furthermore increasing the resolution of objective lens resulted in a highly magnified image with fine texture but a smaller view of the whole ‘e’. ii. Euglena. A ready made slide of Euglena was observed under the microscope. Using high power objective lens, euglena was observed to be a narrow elongated structure being thick in the middle. Due to the presence of chlorophyll the green color was prominent. A colorless flagellum was also observed to extend from the anterior opening of euglena. A red colored eye spot was also observed near the reservoir. The notched anterior opening of euglena serves as mouth which is extended to the reservoir. iii. Paramecium. Using the hanging drop technique, the complex internal structure of paramecium was observed using high resolution objective lens. The water was suspended upside down over the cover slip. Moreover, the cover slip was sealed to avoid leakage. The internal organization of paramecium was observed to contain vacuoles, organized structures characteristic of an animal cell serving as mouth, excretory system and stomach. A well defined nucleus was also observed. iv. Human Blood Cells. Blood examination is the most usual examination done to test the invasion of human body by pathogens. For this purpose blood films are stained using Romanowsky stain on glass slides. This helps in the segregation of different blood cells. Red cells were observed circular disc shaped having a uniform size. Platelets were observed as small discs of bluish-purple color while each type of White cells is distinguished due to the differential count. v. Cheek Cells. In order to observe a human cell, cheek swab is examined under the micros. The swab is introduced in a drop of iodine-water solution over a glass slide which is then covered with a glass cover slip. The low power objective lens yielded numerous odd structured organelles while using a high resolution objective yielded fine structures within the cell. vii. Pond Water. Pond water serves as an enriched source of organisms ranging across various biological kingdoms. Taking a drop from the bottom of the flask a slide is prepared and then examined under high resolution. It showed a variety of creatures including Cyanobacteria identified by their long chains, Algae by the dominant green color, diatoms by their shells and various protozoans. Many insects like fleas were also observed in the slide. Conclusion The study of very small organism and structures require microscopic examination. Microscope magnifies a normal object to an enlarged image making the object visible. In order to view microscopic organisms, the laboratory needs to have a microscope and usually the compound microscope. The lab provided an opportunity to have a view of life that is invisible without the aid of microscope and understanding of different parts of microscopes. Moreover the precautions regarding the handling of compound microscope were also provided. Works Cited Armstrong, W.P. Physical Properties & Structure of Cells. 22nd Jan 2012. Web. 9th Sept. 2012. Morton, David., Perry, Joy B. and Perry, James W. Laboratory Manual for Human Biology, 2nd ed. 2011. Cengage Learning. Print. Wanamaker. Lab: Using a Compound Light Microscope. 2008. Web. 9th Sept. 2012. Wood, John George. Common objects of the microscope. 1861. G. Routledge & sons. Print. 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