ESTIMATING SIZES AT LOW POWER

ONCE THE DIAMETER OF THE FIELD OF VIEW IS DETERMINED (SEE “DETERMINING THE SIZE OF THE FIELD OF VIEW”), IT IS POSSIBLE TO ESTIMATE THE LENGTH AND WIDTH OF MICROSCOPIC SPECIMENS.

(Note to teachers: Any materials with roughly a straight axis can be used for this section. Prepared slides or wet mounts may be used depending on the preparation of the students.)

PART 1: GOOD ESTIMATES

RECORD THE DIAMETER OF THE FIELD OF VIEW OF YOUR MICROSCOPE AT MEDIUM POWER ______________________MM.

1. FOR EACH OF THESE PREPARED SLIDES, RECORD YOUR ESTIMATED LENGTH OF THE LONGEST POSSIBLE MEASUREMENT OF THE SPECIMEN THAT YOU SELECT. IF POSSIBLE, RECORD A WIDTH ALSO.

A. onion cell

B. whitefish blastula cell

C. pollen

D. salt crystal

E. mineral grains in granite

F. a computer chip

G. amoeba

H. diatom

I. human hair

(ADVANCED) RECORD THE DIAMETER OF THE FIELD OF VIEW AT HIGH POWER: ___________________MM

2. FOR EACH OF THE FOLLOWING, RECORD THE LENGTH AS YOU DID IN NUMBER 1

A. stomate and guard cells

B. nucleus

C. chloroplast

PART 2: BETTER ESTIMATES

ON GRAPH PAPER, DRAW A LINE THAT REPRESENTS THE DIAMETER OF THE FIELD OF VIEW AT MEDIUM POWER AS FOLLOWS:

1. DRAW A LINE 40 SPACES LONG.

2. PLACE A ZERO(0) AT THE LEFT END OF THE LINE.

3. COUNT TEN SPACES AND PUT A ONE(1).

4. COUNT TEN MORE SPACES AND PUT A TWO(2), TEN MORE AND PUT A THREE(3), AND FINALLY 10 MORE AND PUT A FOUR(4) AT THE END OF THE LINE.

5. RETURN TO THE MICROSCOPE AND THE SPECIMENS FROM PART 1. FOR EACH SLIDE, LOCATE A SPECIMEN AND DRAW IT ONTO YOUR NUMBER LINE. SIZE MATTERS AT THIS POINT, NOT DETAIL!!!!

6. RECORD THE SIZE OF EACH ITEM AS A DECIMAL.

onion cell ___________mm
whitefish blastula cell _____________mm
pollen _______________
salt crystal _________________
mineral grains in granite _________________
a computer chip ________________
amoeba _________________
diatom ________________
human hair __________________

PART 3: USING THE LENGTHS FOR ................

A. CONVERSIONS

COMPLETE THE FOLLOWING CHART.

REMEMBER:

1m = 100cm = 1000mm = 1000000mm = 1000000000nm

1m = 10⁰m, 1cm = 1 x 10^-2m, 1mm = 10^-3m, 1mm = 10^-6m, 1nm = 10^-9m

SAMPLE:
skin cell *0.1mm **.0001m ***1 x 10^-4m ^100mm ^^100000nm

*as determined from microscope and graph paper
**since 1mm = .001m, then .1mm is .1 x .001 = .0001m
***since 1mm = 1 x 10^-3m, then .1mm is 1 x 10^-4m
^since 1mm is 1000mm, then .1mm is 100mm
^^since 1mm is 1000000nm, then .1mm is 100000nm

specimen actual size in scientific notation size in size in
size (mm) meters (1 x 10⁰ = 1m) micrometers nanometers

onion
cell

whitefish
blastula
cell

pollen

salt
crystal

mineral
grains

computer
chip

amoeba

diatom

human
hair

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