1. Observing and Measuring Cells Lab

2. 1. Measure Using Reticule
Reticule- ruler within the ocular lens
Use to measure specimen observing under the microscope
Length Reticule Measurement (400x):_________
Width Reticule Measurement (400x):________

3. 2. Use the conversion table provided to determine µm
Reticule Measurement:_________
How to use the table!
Get the # of A, B, & C’s
to add up to your total
reticule measurement
Example: Reticule Meas.
= 1.6
1 C + 1 B + 1 A C 1 A B
Objective Lens Power
Microscope Magnification A B C
Scanning
40x
25um
125 um
250 um
Low
100x
10um
50 um
100 um
High
400x
2.5um
12.5 um
25 um
Oil
1000x
1um
5 um
10 um

4. 3. Convert to mm (life size!)
Bigger- move decimal point to the left
Unit
Deci
0.1
(d)
Centi
0.01
(c)
Milli
0.001
(m)
Decimilli
0.0001
(dm)
Centimilli
(cm)
Micro
(µ)
Smaller- move decimal point to the right
Multiply um by _________________ to get mm, or move the decimal place over ____ spaces.
Table Converted Reticule Length:___________
This gives you the Life Size of the object

5. Calculating Drawing Magnification (Length Only!)
100 ÷largest life size
Example: 100 ÷ __________ =
Round to workable #
__________________
Written as _____________ x L.S.

6. Calculate Drawing Dimensions
Life size x drawing magnification
____________ x ____________
These are the dimensions that you will draw
Include labels (follow the rubric)

7. Width Calculations Only determine life size
Do NOT calculate magnification
Use the magnification from length

8. Cell Drawing

9. Cell Drawing
Within 100mm x 100 mm box, measure and draw the length & width of the object (mm)
Include organelles you could see under the microscope
Follow rubric provided