Microscopy http www microbehunter comwpwpcontentuploads201004sempollen jpg Microscopy Microscope
Microscopy http: //www. microbehunter. com/wp/wp-content/uploads/2010/04/sem_pollen. jpg
Microscopy Microscope • an instrument that gives • the study of objects or an enlarged image of organisms (e. g. , bacteria, the object under study protists, cells, etc. ) too – Compound microscope small to be seen by the – Electron microscope naked eye using a tool – Scanning probe called a microscope http: //www. kennislink. nl/ ,
Type of microscope Magnification Generated image Key features How it works Optical compound microscope Up to 1 000 x Magnified color view Samples on glass slides are sometimes stained Visible light and lenses produce a magnified image of an object Scanning electron microscope Up to 50 000 x Sharp 3 D black and white image Surface structures of a sample Thin beam of electrons scanned across the surface of the sample; reflected electrons make up image Transmission Up to 10 000 x Sharp 2 D black and white image electron Details inside cells and nanoparticles Beam of electrons passed through sample, image is magnified, focused by a lens and captured by a computer Looks at individual atoms A probe with a tip only an atom wide scans across a sample’s surface microscope (1 micrometer thick samples) Scanning Up to 90 000 x 3 D black and white computer image of probe atoms on surface of microscope sample
Compound light microscope • Magnification – Enlargement of the image of the specimen – Total magnification = objective lens magnification * ocular lens magnification • Resolution – ability to see a gap separating two dots in an image that, to the naked eye, are not separated. – Influenced by frequency of light waves and quality of the lens • Contrast http: //www. cls. zju. edu. cn, http: //science. howstuffworks. com – Condenser and diaphragm modify size and intensity of a light beam
Using the microscope 1. Carrying the microscope properly 2. Mounting the slide 3. Viewing the specimen *images are backward and inverted *FOV gets darker as magnification increases 4. Preparing the microscope for storage Illuminating the field of view Brighter Darker Mirror Correct angle, Wrong angle, concave side plane side Iris diaphragm Fully open Objective Lower Higher magnification Condenser Closer to stage Partially closed Farther from stage
Preparing samples for viewing Staining cells for better visibility 1. Place several drops of stain on one edge of the cover slip 2. The process of diffusion will allow the stain to go under the cover slip and stain the specimen 3. (tissue paper may be placed on the opposite edge of the cover slip to help the stain diffuse under the http: //www. biosci. ohiocover slip) state. edu/~plantbio/osu_pcmb/pcmb_lab_resources/images/pcmb 1
Microscope Math • Theoretical magnification = ocular X objective • Estimating the diameter of the field of view (LPO diam)(LPO mag) = (HPO diam)(HPO mag) • Estimating cell size = diameter / # of cells spanning the diameter http: //3. bp. blogspot. com/Ff. K 5 d. ESr. ZLM/Tbw. Gr. Fcru. QI/AAAAACY/F 9 b. Yy. Bqnq. AQ/s 1600/hydrilla+leaf. bmp
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