Retinal
Image
Eyepolnt
Body tube
Eyepiece
Pointer
Arm
Objective
I
Nosepiece
Slideclip
Iris
diaphragm
Object
Stage
I
'\/
-'
In-stage
condenser
.
'0;
- y
t'\:'
Ii,
./
illuminator
.- -.---
Fine
\,
adjustment
l'
.
.'
Coarse
adjustment
r_
Light
switch
I
Base
Figure 1.1. The microscope. American Optical Model Series Sixty Microscope.
Used by permission of the American Optical Corporation.
2. Clean the lenses before using your microscope. Use only lens paper. Handkerchiefs, paper toweling, or other material may scratch the lenses. Oil from your face or eye makeup may smear
over the ocular lens and blur the image, making it necessary to clean the lens again.
3. Do not insert or remove a slide with the high power objective in position and never allow an
objective to touch a cover slip. A cover slip is very thin and fragile. An objective touching a
cover slip could easily damage the slide and scratch the lens.
4. Inspect the slide with your unaided eye to determine the number of objects and their positions
on the slide. You can also get an idea of the shape and relative size of the objects.
5. Insert the slide under the stage clips and position the slide so the object will be directly above
the center of the condensor lens. The low power (or scanning) objective should be in position.
2
Metric System**
All linear measurements in the laboratory will be given in metric units. Obtain a ruler marked in centimeters and millimeters. How many centimeters are represented?
One centimeter equals how many millimeters?
To express the size of small objects, such as cell contents, biologists use even smaller units of the metric system than
those on the ruler. These units are the micrometer (ltm) and nanometer (nm). According to figure 1.1, one
millimeter =
micrometers =
mm
nanometers. According to table 1.1, one micrometer =
and one nanometer =
Itm.
To demonstrate that you understand the relationship of one metric unit to another, as described in figure 1.1 and
table I.l,fill in the blanks below.
1.5 mm
=
Itm
1000 nm =
Itm
0.25 mm =
Itm
1,500 Itm =
mm
55 nm
=
Itm
7.5 Itm
=
nm
1.5 cm
=
mm =
Itm
5,000 nm =
Itm =
mm
cm
Measure the diameter of this circle to the nearest millimeter.
Thiscircleis_
mm;
Itm;
nm.
---
Figure 1.1
Life-size ruler. The relationship of nanometers to micrometers to millimeters is indicated.
1,000 micrometers
1 X 10" nanometers
Table
1.1
Unit
Units of measurement
Symbol
Value
Centimeter
em
0.01 m
Millimeter
mm
0.1 em
Micrometer
/lm
0.001 mm
Nanometer
nm
O.OOI/lm
I,OOO~000
--
r\ff\