Lab 2 and 3 Microscope Parts and Function PDF

 Microscope A microscope is an instrument used to see objects that are too small for the naked eye. Types of Microscope 1. Optical Microscopes 2. Stereo Microscopes 3. Scanning Electron Microscopes (SEM)  Types of Microscope 1. Optical Microscopes: Thes...

 Microscope A microscope is an instrument used to see objects that are too small for the naked eye. Types of Microscope 1. Optical Microscopes 2. Stereo Microscopes 3. Scanning Electron Microscopes (SEM)  Types of Microscope 1. Optical Microscopes: These use light and lenses to magnify objects. They can be further classified into two: Compound Microscopes: Use multiple lenses to achieve high magnification. Stereo Microscopes: Provide a 3D view of the specimen and are used for lower magnification.  Types of Microscope 2. Electron Microscopes: These use electron beams instead of light to achieve much higher magnifications. They are included: Transmission Electron Microscopes (TEM): Pass electrons through a thin specimen. Scanning Electron Microscopes (SEM): Scan the surface of a specimen with electrons. Scanning Probe Microscopes: These use physical probes to scan the surface of a sample at an atomic level.  Compound Microscope Light Microscope - A compound microscope is a type of optical microscope that uses multiple lenses to achieve high magnification. t uses visible light and lenses to create magnified images of specimens. 1. Eyepieces (ocular lenses) 2. Body tube 3. Arm 4. Nosepiece 5. Objectives (objective lenses) 6. Course-adjustment knob 7. Fine-adjustment Knob 8. Condenser 9. Light source 10. Diaphragm (diaphragm control lever) 11. Base 12. Stage 13. Stage clips 14. Mechanical stage 15. Mechanical stage control knobs  Anatomy of Light Microscope Eyepiece (Ocular Lens): The lens you look through, typically providing 10x or 15x magnification. Objective Lenses: Multiple lenses mounted on a rotating nosepiece, each with different magnification levels (e.g., 4x, 10x, 40x, 100x). Revolving Nosepiece: The rotating part that holds and allows the selection of different objective lenses. Stage: The platform where the microscope slide is placed. It often has clips or a stage holder to secure the slide. Stage Clips: Clips that hold the slide in place on the stage.  Anatomy of Light Microscope Condenser: A lens system below the stage that focuses light onto the specimen. Diaphragm (Aperture Iris): Controls the amount of light passing through the specimen, located beneath the condenser. Illuminator (Light Source): Provides the light needed for imaging, typically a built-in lamp or LED. Base: The bottom part of the microscope that provides stability and houses the illuminator.  Anatomy of Light Microscope Arm: Connects the base to the body tube and supports the optical components. Coarse Focus: Allows for large adjustments in focus by moving the stage or objective lenses. Fine Focus: Provides precise control for fine-tuning the focus. Body Tube: Connects the eyepiece to the objective lenses, holding them in alignment.  Magnification Magnification in a microscope refers to the process of enlarging the appearance of an object to allow detailed examination of its structure. It is a measure of how many times larger the object appears compared to its actual size.  How Magnification Works? Objective Lenses: These are the primary lenses near the specimen that provide initial magnification. Common objective lens magnifications are 4x, 10x, 40x, and 100x. Eyepiece (Ocular Lens): This lens is where you look through the microscope and further magnifies the image produced by the objective lenses. Eyepiece magnifications are typically 10x or 15x.  Resolution The resolution of a microscope is the ability to distinguish between two closely spaced points as separate entities. It defines the level of detail that can be observed and is a crucial factor in determining the clarity of the image produced by the microscope. How to achieve good Resolution Key Concepts of Resolution 1.Resolution Definition: 1.Resolution is the minimum distance between two points where they can still be seen as separate. The higher the resolution, the clearer and more detailed the image. 2.Resolving Power: The resolving power of a microscope is its ability to distinguish fine details and is inversely related to the minimum resolvable distance. A microscope with high resolving power can see finer details.  Field of View Field of View: The field of view (FoV) of a microscope is the diameter of the visible area seen through the eyepiece or ocular lens when looking at a specimen. It is essentially the size of the area you can observe at one time through the microscope. increases  RELATIONSHIP: As magnification __________, field of decreases view __________.  As you switch from scanning (40X) to high power (100X), the area you see through the microscope gets smaller.  Typical Field of View Sizes Low Magnification (e.g., 4x or 10x objective): Provides a larger field of view, typically ranging from 1.5 mm to 10 mm in diameter. This is useful for scanning large areas of the specimen. Medium Magnification (e.g., 20x objective): Provides a moderate field of view, generally around 0.5 mm to 2 mm in diameter. High Magnification (e.g., 40x or 100x objective): Offers a smaller field of view, usually less than 0.5 mm in diameter. This allows for detailed examination of small structures.  Using the Microscope General Procedures ✓ Make sure all backpacks and materials are out of the aisles and off the tops of desks. ✓ Store with cord wrapped around microscope and the scanning objective clicked into place. ✓ Carry by the base and arm with both hands.  Using the Microscope Focusing Specimens ✓ Always start with the Scanning Objective. ✓ Place your specimen in the center of your field of view. ✓ Use the Coarse Knob to focus. ✓ Next, use the Fine knob until clear. ✓ Once you've focused on Scanning, switch to Low Power. ✓ Repeat steps 3-4. ✓ Now, switch to High Power. ✓ At this point, ONLY use the ____ ___________ _____ to focus specimens. Fine Adjustment Knob  Using the Microscope Recap DO NOT SKIP 1. Scanning --> use coarse and fine knob STEPS!!!! 2. Low power --> use coarse and fine knob 3. High power --> use fine knob only What will happen if I use the course knob under high power? The slide or lens could crack  Practice with Letter “e” When you view the letter "e," it appears inverted (upside down) and flipped horizontally (like a mirror image). This effect happens due to the optical design of the microscope. 1. Lens Refraction: As light passes through these lenses, it bends (refracts) multiple times. 2. Optical Path: The path that light takes through the microscope involves crossing over itself as it passes through the objective and eyepiece lenses. 3. Human Perception: Our eyes and brain are used to interpreting light that comes directly from objects. when viewing something through a microscope, we're seeing light that has been altered by the lenses, which leads to the image appearing inverted.  Practice with Letter “e” Field of View changes with magnification Wet Mount 1. A wet mount is a technique used in microscopy to prepare a specimen for viewing under a microscope. 2. It involves placing the specimen in a drop of liquid on a slide, covering it with a cover slip, and then viewing it under the microscope. 3. Wet mounts are commonly used to observe living organisms or to view specimens in their natural, hydrated state. Making a Wet Mount Slide Steps to Prepare a Wet Mount: Prepare the Slide: Start with a clean glass slide. Place a drop of water (or another suitable liquid, such as saline or a staining solution) in the center of the slide. Add the Specimen: Place the specimen in the drop of liquid. If the specimen is too large, you may need to use a small piece or crush it to fit within the drop. Making a Wet Mount Slide Apply the Cover Slip: Hold a cover slip (a thin, square piece of glass or plastic) at a 45-degree angle to the slide and carefully lower it onto the drop. This technique helps avoid air bubbles, which can obstruct the view. The liquid should spread evenly under the cover slip, forming a thin layer. Examine the Slide: Place the slide on the stage of the microscope. Start with a low-power objective lens to locate the specimen, then switch to higher magnifications as needed. Staining Specimens Scientists stain specimens to see parts of the cell more clearly. 1. Put a drop of stain (iodine) on a slide. Caution: methylene blue will stain clothes and skin. 2. Place specimen in the center of drop of stain. 3. Place a coverslip onto the slide.  Water bottle sorbent Cover slips paper Stain Dissecting Slides needles Tweezers  Onion 1. Obtain a cleaned slide and a cover slip. 2. Cut off a small piece of onion. 3. Peel off the inner surface (looks like a tissue paper) with a forceps or use your finger nails. 4. Place the piece of onion on a clean dry slide 5. Add a drop iodine 6. Cover the slide with a coverslip 7. Observe under the microscope 8. Describe what you see ? Onion Cells Wet Mount Iodine Practice Cheek Cells Wet Mount 1. Obtain a cleaned slide, cover slip and toothpick. 2. Enroll a toothpick inside our inner part cheek. gently scrape 3. Place the specimen (scrapings) on a clean dry slide 4. Add a drop of stain (Methylene Blue) 5. Cover the slide with a coverslip 6. Observe under the microscope  Cleanup 1. Store microscopes with the scanning objective in place. 2. Wrap cords and cover microscopes. Double check to make sure you didn't leave a slide 1. Place microscopes in their designated location (probably a cabinet) Wet Mount Onion Cells: https://youtu.be/PrX3h-AflZI?si=jjM7bt1lLkIq_D39 Wet Mount Cheek Cells: https://youtu.be/3aQYc6DeWsY?si=k7Msyt4SmutOW-YI Practice Labeling the Parts  Quiz Over the Microscope 1. When focusing a specimen, you should always start with the ___________________ objective. 2. When using the high-power objective, only the ________ ___________ knob should be used. 3. The type of microscope used in most science classes is the _________________ microscope 4. What part of the microscope can adjust the amount of light that hits the slide? _____________________________ 1. You should carry the microscope by the ________ and the __________. 2. The objectives are attached to what part of the microscope (it can be rotated to click the lenses into place): _______________ ________________ 3. You should always store your microscope with the ________________ objective in place. 4. A microscope has an ocular objective of 10x and a high- power objective of 50x. What is this microscope's total magnification? ____________