MICROSCOPES

magnification

enlargement of size

resolution

ability to see detail

compound light microscope

more magnification, resolution, different lens

base supports

stage with clamps to hold specimen

on/off switch

illumination intensity control knob control light

iris diaphragm

creates aperture where light passes through condenser

condenser

small lens focus incoming light onto specimen

objective lens and nosepiece, ocular lens

different magnifications om rotating nosepiece

4x, 10x, 40x, 100x (needs oil)

ocular lens 10x

working distance

distance between the front edge of the objective lens and coverslip with specimen in focus

focusing

image in view and increasing sharpness

focus knobs

sides near base of arm

adjust working distance

coarse: moves objects over larger distance than fine

fine:only one used when high mag

body tube

connect objective lens to eyepieces/ocular lens

total magnification of microscope

objective lens mag x eyepiece mag (40x x 10x = 400x)

compound vs dissecting

compound penetrate light, short working distance, higher mag, smaller depth of field

dissecting use external light, larger working distance, lower mag, higher depth of field; 3D image

using compound light microscope

• carry both hands

• gently handle

• plug in

• lowest power objective

• light on, adjust

• place slide with specimen

• adjust angle

• always start lowest mag

• slowly increase mag wit coarse then fine

• when finished go back to lowest then remove slide, turn light down and off

procedure

familiarize

calculate total magnification

practice compound looking at an “e”

• should be upside down and flipped

• moving up/down right/left should be opposite of normal

field of view

• measure by diameter with ruler

calibrate ocular micrometer

• using divisions and ruler in microscope and divide

measure diatom

• use micrometer

depth of field

• lower power objective has higher depth of field, focus on more things

onion skin

• stain nucleus, place skin on water droplet

cheek cells

• scrape and put on slide, stain

paper clip in dissecting microscope

• should move in same directions as normal