Science Subject_ Lesson on Compound Microscope

Science_ Lesson on Compound Microscope

1. Exploring the Compound Light Microscope Understanding the microscope’s role in scientific discovery

2. Introduction & Learning Objectives

3. Learning Objectives Identify Microscope Parts Students will learn to identify all key parts of a compound microscope and understand their functions. Focus Specimens Students will practice focusing specimens using the compound microscope to observe fine details clearly. Proper Handling and Storage Students will demonstrate correct handling and storage techniques to maintain microscope condition and longevity.

4. Historical Development of the Compound Light Microscope

5. Pioneers of Microscopy First Compound Microscope Zacharias Janssen invented the first compound microscope around 1590 using multiple lenses in a tube. Discovery of Microorganisms Anton van Leeuwenhoek improved lens quality and first observed microorganisms called 'animalcules' in the 1670s. Father of Microscopy. Coining the Term Cell Robert Hooke used a microscope to observe cork cells and introduced the term 'cell' in 1665.

6. Zacharias Janssen This Photo by Unknown Author is licensed under CC BY-SA

7. Anton van Leeuwenhoek

8. Robert Hooke

9. Parts of a Compound Light Microscope (CLM)

10. Two Types of Microscopes Simple Microscopes Compound Microscopes

11. Simple Microscope Compose of one lens and provide relatively low magnifying powers. Example: Magnifying glass This Photo by Unknown Author is licensed under CC BY-SA

12. Compound Microscope - composed of two or more lenses that provide powerful magnification.

13. The parts of a CLM Illuminating Parts Magnifying Parts Mechanical Parts

14. Illuminating Parts a) Mirror The mirror reflects external light into the microscope to illuminate specimens for clear viewing. b) Condenser Role The condenser focuses light onto the specimen to enhance illumination and clarity.

15. Illuminating Parts c) Diaphragm Control The diaphragm regulates the amount of light entering the condenser for optimal brightness. d) Eyepiece and Objective Lens The ocular eyepiece and objective lens magnify the specimen for detailed observation.

16. Magnifying Parts a) Ocular Lens Function The ocular lens in the eyepiece provides a fixed 10x magnification for viewing specimens. b) Objective Lenses Types Objective lenses vary in magnification: scanner 4x, low power 10x, high power 40x, and oil immersion 100x.

17. Magnifying Parts c) Total Magnification Range Combining ocular and objective lenses allows total magnifications from 40x to 1000x for detailed specimen observation.

18. Mechanical Parts Structural Components The body tube connects the eyepiece to objectives, while the arm allows safe carrying of the microscope. Slide Handling Parts The stage holds the slide and stage clips secure it firmly during examination.

19. Mechanical Parts c) Focusing Mechanisms Coarse and fine adjustment knobs enable general and precise focusing for clear observation. d) Support and Lens Rotation The base provides stability and the revolving nosepiece holds multiple objective lenses for easy switching.

20. Specimens & Slide Preparation

21. Types of Specimens a) Plant Cell Specimens Plant cells like onion skin and leaf tissue reveal cell walls and chloroplasts under the microscope. b) Animal Cell Specimens Animal cells such as cheek cells show nucleus and cell membrane details when properly prepared.

22. Types of Specimens c) Microorganisms in Pond Water Microorganisms from pond water demonstrate microbial diversity and motility under magnification. d) Specimen Preparation Proper mounting and preparation techniques ensure clear visibility and accurate study of specimens.

23. Preparing Slides for Investigation Dry-Mount Slide Preparation Dry-mount slides involve placing a dry specimen directly on the slide and covering it with a cover slip for observation. Wet-Mount Slide Preparation Wet-mount slides include adding a drop of water, placing the specimen, and gently applying a cover slip at an angle to avoid bubbles. Slide Preparation Skills Practicing both dry and wet mount slide techniques enhances specimen preservation and visibility under the microscope.

24. Microscope Operation & Image Appearance

25. Basic Microscope Operation Microscope Setup Place the microscope on a flat surface and adjust the light source for proper illumination. Slide Placement Secure the specimen slide on the stage using stage clips to keep it steady during observation. Initial Focusing Start with the scanner objective and use the coarse adjustment knob to bring the specimen into view clearly. Fine Focusing Switch to higher power objectives and use the fine adjustment knob to sharpen the image precisely.

26. Appearance of Specimens Under CLM Image Inversion and Reversal Specimens appear inverted and reversed because of the compound microscope's lens setup. Magnification and Field of View Higher magnification reduces field of view, enabling detailed observation of specimen areas. Importance of Proper Focusing Proper focusing prevents blurry images and helps distinguish cellular structures clearly. Accurate Interpretation Understanding image orientation aids students in interpreting microscopic observations accurately.

27. Magnification and Field of View

28. Magnification - the process of making an object appear larger than it really is, using lenses. In a microscope, magnification helps us see tiny details of specimens that are invisible to the naked eye.

29. Magnifying Power of CLM Magnification Calculation The total magnifying power is found by multiplying the ocular lens by the objective lens magnification. Example Calculation A 10x ocular lens combined with a 40x objective lens yields a total magnification of 400x. Practical Application Understanding magnification helps students choose the right lens for detailed observation during investigations.

30. Calculating Field of View Definition of Field of View Field of view is the visible area seen through the microscope lens at a given magnification. Effect of Magnification Increasing magnification decreases the field of view, reducing the visible specimen area. Practical Example At 40x, field of view is about 4 mm; at 400x, it decreases to roughly 0.4 mm. Importance in Measurement Estimating field of view enables accurate measurement of specimen dimensions under the microscope.

31. Proper Handling and Storage

32. Handling and Storing the Microscope Safe Carrying Techniques Always carry the microscope with two hands to prevent accidental drops and damage. Lens Cleaning Practices Clean lenses only with lens paper to avoid scratches and maintain clear viewing. Proper Storage Conditions Store the microscope in a dry, dust-free cabinet to protect delicate components after use.