Microscopy

Question 1

How do you calculate the actual size of an object?

Answer 1

-put into same units
-image/magnification

Question 2

How are images formed in a microscope?

Answer 2

light/electrons pass through object being viewed, some parts of object absorb more light/electrons than others and are therefore visible, stains enhance this

Question 3

What stain is used for electron microscopes?

Answer 3

objects dipped in solution of heavy metal eg. lead, metal ions scatter electrons to create contrast

Question 4

How do you prepare a dry mount slide?

Answer 4

-take thin slice of specimen so light can pass through
-use tweezers to place specimen in middle of slide
-put cover slip on top

Question 5

How to prepare wet mount microscope slide

Answer 5

-pipette small drop of water onto slide
-place specimen on top
-put cover slip on by carefully lowering to avoid air bubbles
-put drop of stain next to cover slip

Question 6

How to use light microscope

Answer 6

-clip slide onto stage
-use lowest powered objective lens
-use coarse adjustment knob to move stage and look through eye piece
-use fine adjustment knob to get clear view
-switch to higher powered objective lens to get greater magnification

Question 7

What is the eyepiece graticule?

Answer 7

transparent ruler with numbers, fitted onto eyepiece

Question 8

What is the stage micrometer?

Answer 8

microscope slide with units, that’s placed on the stage

Question 9

How do you use eyepiece graticule and stage micrometre?

Answer 9

-work out what 1 EPGU is in terms of stage micrometre divisions, which are unchangeable, accurate units
-1 micrometre division= x EPGUs
-(x EPGUs)/(1 micrometre division in real units)

Question 10

How do you calculate the uncertainty of the stage micrometre?

Answer 10

value of smallest division/2