1. Basic Laboratory Skills: Making Microscopic Measurements : Lab 2d
Word of the Day:
Magnification: the process of enlarging something
Basic Laboratory Skills: Making Microscopic Measurements : Lab 2d
MICROSCOPIC MEASUREMENT AND DRAWING

2. How big is a cell?

4. How can we determine the size of a specimen under the microscope?
Most accurate:
Micrometer
Ruler
Built into ocular
Alternative:
Estimate using
the technique
we will do today!

5. Our Method - Low Power
Make a wet-mount of a piece of 1-mm graph paper (10mm2)
Count how many millimeters across appear in your field of view in low power (40X - with eyepiece)
Convert to micrometers
How many micrometers in a millimeter?
Record this in results!

6. Making Microscope Measurements
Total view =
2 boxes =
4 mm across=
4000 μm
1 Box = 2 mm
40X 6

7. Field of Vision Sizes
Field of visions for higher powers are based off of the 40X field
100X is 2.5 times smaller then 40X
400X is 10 times smaller then 40X
40X
2.5 times smaller
10 times smaller
100X
400X 7

8. Fields of Vision 40X = 2 boxes = 4 mm  4000 μm
100X = 2 boxes/2.5 = .8 boxes = 1.6 mm  1600 μm
400X = 2 boxes/10 = .2 boxes = 0.4 mm  400 μm
*All measurement are for width across the middle* 8

9. Field of Vision at High Magnifications
You know that…
The field of vision is ~400 μm wide
You estimate that…
The cell takes up about 1/3 of the width
You can calculate that…
The cell is about μm
400*1/3 = μm
400X 9

10. Procedure Make a wet mount of mm grid graph paper.
Count how many 1-mm square go across the diameter of the low power field.
Convert the diameter measurement from mm to µm.
1 mm = 1000 µm
4. Create a data table and record the size of the low power field in both mm and µm mm µm
40x
100x
400x

11. Procedure (cont.)
5. Do the division (do NOT measure!) to calculate the sizes of the medium and high power fields.
40X
2.5 x smaller
10x smaller
400X
100X
6. Report the values in both mm and µm in data table

12. Next!!!!!!! Choose a slide and draw your organism Use details
Use shading
List power drawn under
Make large

13. Example
Paramecium
400X