Compound Microscope Guidelines PDF

Compound microscope: Guidelines for Use. 1. Always carry with 2 hands. and wrap the cord around the base 2. Only use lens paper for cleaning and always store covered Compound microscopes have two sets of lenses for magnification.  Lens closer to the eye = ocular lens (magnifying power of 7x an...

Compound microscope: Guidelines for Use. 1. Always carry with 2 hands. and wrap the cord around the base 2. Only use lens paper for cleaning and always store covered Compound microscopes have two sets of lenses for magnification.  Lens closer to the eye = ocular lens (magnifying power of 7x and 10x).  Lenses closer to the object being viewed = objective lens. (Most light microscopes used in biology have three or four objective lenses).  Base: Supports the microscope  Arm: Used to support the microscope when carried. Holds the body tube, nose piece and objective lenses‫ز‬  Light Source :Projects light upwards through the diaphragm, the specimen and the lenses‫ز‬  Diaphragm:The Diaphragm controls the amount of light on the slide/specimen  Stage: Supports the slide/specimen  Stage Clips: These 2 clips hold the slide/specimen in place on the stage.   Body Tube:The body tube holds the objective lenses and the ocular lens at the proper distance.  Rotary nose piece: The Nose Piece holds the objective lense and can be turned to increase the magnification Rotary nosepiece of your microscope has Four objective lenses attached. Red band around it, Magnifies objects 4x. Low Power Objective Lens, Magnifies objects 10x. High Dry Objective Lens, Has blue band around it, Magnifies objects 40x Immersion Oil objective lens , magnifies objects 100x. Why we use oil with 100x lens? The light passes from glass (slide) → air → glass (objective lens), so in order to eliminate any air gaps and loss of light due to refraction (bending of the light), the 100x lens is immersed in a drop of oil placed on the slide because Immersion oil has the same refractive index of glass.   Magnification and objective lenses Ocular lens magnifies the specimen 7x or 10x. You will always be looking through the ocular and objective lens  The total magnification power is= the ocular x objective.  Adjustments  Coarse Adjustment Knob: Moves the stage up and down (quickly) for focusing your image  Fine Adjustment Knob This knob moves the stage slightly to improve the image. During examination 1. Scanning : use coarse and fine knob, Use the Coarse Knob to focus and the fine adjustment knob until clear, 2. Low power - use coarse and fine knob 3. High power - use fine knob only. Troubleshooting Occasionally you may have trouble with working your microscope. Here are some common problems and solutions. 1.Image is too dark! : Adjust the diaphragm, make sure your light is on. 2.There's a spot in my viewing field, even when I move the slide the spot stays in the same place! Your lens is dirty. Use lens paper, and only lens paper to carefully clean the objective and ocular lens. The ocular lens can be removed to clean the inside. The spot is probably a spec of dust. 3. I can't see anything under high power! Remember the steps, if you can't focus under scanning and then low power, you won't be able to focus anything under high power. Start at scanning and walk through the steps again. 4. Only half of my viewing field is lit, it looks like there's a half-moon in there? You probably don't have your objective fully clicked into place Other apparatus used in microbiology laboratory : Hot air oven :  For sterilization by dry heat, electrically heated and provided with thermostat.  used to sterilize glassware,oils. Powders , test tubes, flasks, pipettes and all dry material in sealed container holding period. 1.5 to 3 hours at temperature 160-180°c. Autoclave :  Bacteria are more readily killed by moist heat (saturated steam) than dry heat, steams kills bacteria by denaturing their protein.  Used to sterilize culture media and aqueous solutions (holding time 15 minutes at 121 ْc – 15 Ib. Incubator :  For medical use incubators are usually operated at 35 -37 ْc. Water bath :  Used for short term incubation for some important tests. Balance:  Used for weight ( media , powders )...ect Equipment’s used in microbiology laboratory  Burner.  Loop (sterilized by red heat).  Slides and cover slides.  Glass marker.  Sets for staining , droppers and staining rack  Different types of culture media.  Plates for weighting.  Flasks with different volume for preparation of culture media  Petry dishes (glass and disposable).  Test tubes and pipettes.  Cider oil  lens paper  soaps and disinfectants. -