Microscopy is the ____________________________________________________________________________________________________ ______________________________________________________________________________________________________ There are two types of microscopes 1. __________________________________________: uses light and lenses to magnify an object, 2D 2. __________________________________________: sends electrons over the surface of a specimen, creates a 3D image, HIGH magnification power (some up to 1,000,000 times!) Magnification is the ability to _______________________________________________________________________________________ We will be using light microscopes. This type of microscope magnified objects by ____________________________ the light that passes through the lens Convex lenses cause light rays to _____________________________________or bend ___________________________________ Compound light microscopes have more than ______________ lens. As a result, they can magnify objects _______________________ than microscope with a single lens. -­‐Light passes through the ____________________________________ and travels through the two lenses. Determining TOTAL MAGNIFICATION: have to make sure that each lens’ effect is measured -­‐On our microscopes, there are 3 different powers of magnification on the objective lenses 1. Low Power: 4x 2. ________________: 10x 3. High Power: _____________ -­‐However, we also look through the ocular lens, which has a magnification of 10x -­‐So, we must multiply the lenses together in order to get the TOTAL MAGNIFICATION Objective lens x ocular lens = total magnification (medium power lens) 10 x (ocular lens) 10 = 100x -­‐The magnification of each lens is always engraved on the side. Always double check to make sure you are at the proper magnification! Resolution is the ability to distinguish the individual parts of an object; the __________________________________ MAILER.COM Print and send PDF files as Emails with any application, ad-sponsored and free of charge www.pdfmailer.com
or ______________________________________ of an image Label each Science
10of the parts of the microscope: Unit 2 - Biology
This a _____________________________________ microscope. 5. is Label
each of the following parts _________________________________________ on this compound monocular microscope:
6.
Give the function of each of the following microscope parts: (see p. 316-318 in Text)
a)
Ocular Lens –
3. Give the function of each of the microscope parts (use the reference sheet) a. Ocular lens – b. Body tube – c. Low Power Objective Lens ( ______________ X) – d. Medium Power Objective Lens ( _________________ X) – e. High Power Objective Lens ( _________________ X) – f. Revolving Nose Piece – g. Arm – h. Stage – i.
Stage clips – j.
Dish Diaphragm (light control disk) – k. Course adjustment knob – l.
Fine adjustment knob – m. Light – 4. Examining Slides Procedure: A. Obtain a prepared letter “e” slide B. Place the slide on the stage and move it so that the “e” is right over the light source/the little piece of glass in the center. C. Position the Low Power Objective Lens right above the center (so that it clicks into place) D. Look into the Ocular Lens and adjust the Coarse Adjustment Knob until the “e” is in focus. E. Use the little knobs on the stage to move the “e” right into the center of the circle that you see, move the light control disk to give you the best image. F. Now, adjust the Fine Adjustment Knob until the “e” is as sharp as you can get it. Sketch EXACTLY what you see in the first circle on the next sheet. Be sure that the sizes are relative to how you see them and to write down the total magnification. G. Next, switch to the Medium Power Objective Lens and sketch what you see in the second circle. Be sure that the sizes are relative to how you see them and to write down the total magnification. H. Repeat these steps with the High Power Objective Lens and sketch in the third circle. 5. Find Ms. Bell and select a slide from the prepared slide box. Look at it under LOW power and sketch what you see in the circle below. 6. Questions -­ answer in the space provided 1. A compound microscope must always be carried using one hand on the ____________________________________ and the other hand on the _____________________________________ 2. When you move an object to the right on the stage, the image in the field of view moves to the _________________________________. When you move an object up on the stage, the objects in the field of view move ___________________________________________. 3. How does the light control disk change the amount of light reaching the object? 4. Which can you see more of an object in, a lower power magnification or a high power magnification? 5. Give two advantages to viewing an object in a lower power magnification. 6. Give one advantage of viewing an object in high power magnification. 7. If the letter “b” is placed on the stage so that it appears as “b” from the outside; draw what it would look like when viewed under the microscope in the space below: Eyepiece (ocular lens) The part you look through. It has a lens that magnifies the object, usually by ten times
(10x). The magnifying power is engraved on the side of the eyepiece.
Body Tube Holds the eyepiece and the objective lenses at the proper working distance from each other.
Revolving nosepiece Rotating disk holds two or more objective lenses. Turn it to change lenses. Each lens
clicks into place.
Objective lenses Magnify the object. Each lens has a different power of magnification:
Low: 10x
Medium: 40x
High: 100x
The magnifying power is engraved on the side of each objective lens. Be sure you can identify each lens.
Fine-adjustment knob Use with medium- and high-power magnification to bring the object into sharper focus.
Coarse-adjustment knob Moves the tube or stage up or down and brings the object into focus. Use it only with
the low-power objective lens.
Stage Supports the microscope slide.
Stage Clips hold the slides into position. A hole in the center of the stage allows the light from the light source
to pass through the slide.
Diaphragm Use this to control the amount of light reaching the object being viewed.
Light Shining a light through the object being viewed makes it easier to see the details.