Clemson BIOL 1101 - Lab 4 Topic 2: Microscopes and Cells (11 pages)

LAB TOPIC 2 1e can Cells study uted nee cal sts J Mi crosco12 es and Cells 5 b 10 l lilv tj ese light and n in a1ose h is in OiJ r a 0 1e ghere OWV f v v V t OV Y l f N f r A t Q V S AA y V t fuo t S too o e r peci FIGURE 2 1a The compound binocular light microscope Locate the parts of your microscope described in Exercise 2 1 and label this ph otograph Indicate in the margin of your lab manual any features unique to your microscope cular enses 1pe of e of tru re all le FIGURE 2 1b Enlarged photo of compound light microscope as viewed from under the stage Th is microscope is l uq ipped with phase contrast optics Locate the condenser condenser adj ustment knob phase contrast revolving turret and iris diaphragm on your microscope if present and label them on the diagram J LAB TOPIC 2 k For binocular m icroscopes cover your left eye and use the fine adjust Uf epiece time you letter ment knob to focus t he fixed righ t ocular until the letter e is in maximum focus Now cover t he rig ht eye and using the diopter ring on the left ocular bring the Image into focus The letter e should now be in focus for both of your eyes Each new lab day as you begin to study you r first slide repeat this procedure I You can increase or decrease the co ntrast by adjusting the iris diaphragm opening Note that the maximum amount of ligh t provides little con trast Adjust the aperture until the image is sharp t m Move the slide slowly to t he righ t In what direction does the image in er n t he ocular move n Is the image in the ocular inverted relative to the specimen on the stage yslowly he ion the tr lab cale he S il the he both o Center the specimen in t h e field of view th en rotate the 40X ob jective in to position wh ile watching from th e side If it appears that the objective will hit the slide stop and ask for assistance Most of the microscopes have parfocal lenses which means t hat little refocusing is requ ired w hen moving fro m one lens to another If your scope is not parfocal ask your instructor for assistance p After th e 40X objective is in place focus using the fine ad justmen t knob Microscopes and Cells 39 40 LAB TOPIC 2 Microscopes and Cells tio n if the o c ular we re 20 x and he t I inagni c 1 b Whal would be the to a This magnification approac h1cs 1mmers1on objective were 0 0 x o 11 is in a specimen using a light micro g fine d et 11 the uppe r limit to r s ee1 I sco pe V V 1 or d f ieW Once you determine the size O 4 Measure the diameter of the fiel v f lar and ob 1ective lenses you b ation o oct o f the fi eld of view for any com tn that field 11 can d etermine the size of any st ru cture w it m tl and remove the letter slide a Rotate the 4 x objective into poSI O 11 d focus o n its edge b Place a clear ruler on the st age an the ruler is 1 mm What is the c Th e distance between two m es on diameter mm of the field of view used unit of m easurement in microscopy 1 mm 1 000 m e Measure the diameters of the field of view for the lO X and 40X objectives and enter all three in the spaces below to be u sed for e Rotate l using ti have a 6 At the enc store your a Ra lat c Retur phas d Set ti e Un p f Repl future reference D IJ ox 1 a wt1o x both l h l acl justn11 under or b Remo d Convert this measurement to micrometers m a m ore commonly 4X d Foc us up L QO AA V f What is the relationship between the size of the field of view and g Rett sho These steps magnification t c oitlf y k s Determine spatial relationships The depth of field is the thickness of the specim e n that may be seen in focus at o ne time Because the depth of foc us is very short in the compound microscope focu s up and down to clearly view all planes of a specimen a Rotate the 4 X objective into position and remove the ruler Take a slide of crossed threads wipe it with a Kimwipe and place the slide on the stage Center the slide so that the region where the two threads cross is in the center of the stage opening b Focus o n the region where the threads cross Are both threads in focus at the same time EXERC The St Materii stereosco1 dissect in livingf h lntrod Th e ster 7 X to 3 Thebi 1 scope i p The so obi direct view lr object objecl 1 c Rotate the lO X objective into position and focu s on the cross Are both threads in focus at the same t i Does th e 4 X or the lO X objective have a shorter depth of field t f N O f u hf LABTOPIC2 d Focus upwa rd 1110 e the stage up with the coarse ndj ustm cnt until both threads are just out of focus Slowly focus down using the fi ne adjustment Which th read come into foc us first Is th is thread lying undec ove the 1At ceo e Rotate the 40 x objective into positio n and slowly focus up nnd down using the fin e adjustment only Does the lOX or the 40 X objective haveashoctec depth offleld j O M 6 At the end of your microscope session use the following procedures to store your microscope a Rotate the 4 x objective into position b Remove the slide from the stage c Return the phase contrast condenser to the O setting if you have used phase contrast d Set the light intensity to its lowest setting and turn off the power e Unplug the cord and wrap it around the base of the microscope f Replace the dust cover g Return the microscope to the cabinet using two hands one hand should hold the arm and the other should support the base These steps should be followed every time you store your microscope EXERCISE 2 3 The Stereoscopic Microscope Materials stereoscopic microscope dissecting needles Jiving Elodea microscope slides droppers of water coverslips Introduction The stereoscopic dissecting microscope has relatively low magnification x to 30 X and is used for viewing and manipulating relatively large objects The …