More on microscopy Flashcards
PRACTICAL - Prepare a slide ( light microscope )
1) Add drop of water in middle of clean slide
2) Cut an onion and separate it into layers then use tweezer to peel off epidermal tissues from bottom of one of the layers
3) using the tweezer, place epidermal tissues into water on the slide
4) Add a drop of iodine using a pippete onto the slide which is a stain that highlights the object in cells by adding colour to them
5) place a cover slip on top using mounting point needles by standing the cover slip upright on the slide next to water droplet then carefully tilt and lower it as it covers the specimen.
Try not to get air bubbles as they obstruct view of the specimen
PRACTICAL - Using light microscope
1) Clip slide you’ve prepared onto the stage
2) Select lowest power objective lens
3) use coarse adjustment knob to move stage up just below the objective lens
4) Look down the eyepiece and use coarse adjustment knob to move the stage downwards until image is roughly in focus
5) adjust the focus with fine adjustment knob until you get clear image of what’s on slide
6) If you need a slide with a higher magnification , swap to higher powered objective lens and refocus
PRACTICAL - Draw observations
1) draw what you see with pencil with sharp point
2) make sure drawing takes up half of space with clear unbroken lines
3) no colouring or shading
4) if drawing cells, the subcellular structures must be in proportion
5) include title of observation of magnification
6) label important features using straight uncrossed lines
