TitleUsingaCompoundMicroscope采用复合显微镜的标题.doc

Title: Using a Compound MicroscopeBackground:Microscopes are very important tools in biology. The term microscope can be translated as “to view the tiny,” because microscopes are used to study things that are too small to be easily observed by other methods. The type of microscope that we will be using in this lab is a compound light microscope. Light microscopes magnify the image of the specimen using light and lenses. The term compound means that this microscope passes light through the specimen and then through two different lenses. The lens closest to the specimen is called the objective lens, while the lens nearest to the users eye is called the ocular lens or eyepiece.When you use a compound light microscope, the specimen being studied is placed on a glass slide. The slide may be either a prepared slide that is permanent and was purchased from a science supply company, or it may be a wet mount that is made for temporary use and is made in the lab room.Procedure:Place the microscope on the lab table in front of you. Using your textbook identify the various parts of the microscope on the following diagram. Part A: Determining the size of your field of vision.Obtain a piece of mm ruled graph paper, place it on a clean dry slide and add a cover slip. Focus with the 4x objective, and place a vertical line of one square on the very left margin of your field of view. Now estimate to the nearest tenth of a millimeter, the diameter of the field by seeing how many squares are visible across the field of vision.The field of view with the 4x objective is about _ mm. The measurement can be converted to micrometers (um) by multiplying by 1,000. The field of view therefore equals _ um. Now switch to the 10x and follow the same procedure for this objective.The field of view on 10x is about _ mm which equals _um. Now switch to 40x and follow the same procedure for this objective.The field of view on the 40x is about _ mm which equals _ um.Part B: Another aspect of microscope examination is the internal optical system and its alteration of the object seen. Obtain a small piece of newsprint which includes any one of the following letters: e, b, p, d, g, or q. Place on a dry slide in a normal reading position, and add a cover slip. Answer the following questions:What is the appearance of the letter in normal reading position?What is the appearance of the letter as seen through the microscope?While viewing the letter, physically move the slide toward you on the stage. What direction did you observe the letter moving while viewing?Therefore, due to the arrangements of the lenses, an object which appears in the normal reading position will be _ when viewed through the microscope. Part C:Now you are ready to look at various items under the microscope. Draw a detailed picture of each item as it looks under the microscope. In order to receive full credit your drawings must be detailed, realistic, and colored. Analysis:1. Why should you always begin to use a microscope with the low-power objective?2. Why should you only use the fine adjust when the high-power objective is in position?3. Why must the specimen be centered before switching to high power?4. If you placed a letter “g” under the microscope, how would the image look in the field of view?5. If a microscope has an ocular with a 5x power, and has objectives with powers of 10x and50x, what is the total magnification of: (Show your math for full credit!)a. low power?b. high power?6. If you are looking through a microscope at a freshly prepared wet mount and you see se