OCULAR
MICROMETER
INTRODUCTION
Ocular micrometer is
equipment that is used to measure the size of prokaryotic and eukaryotic
microorganisms and compare both species. An ocular micrometer has a ruler that
functional to measure the size of magnified objects. The distance between the
marks on the ruler depends on the degree of magnification. There are between 50
to 100 individual marks on the ruler of typical ocular micrometer that is 2mm
long and have the distance between each marks is 0.01mm. The ocular micrometer
consists of 2 main scales that are ocular scale and stage scales. For ocular
scale, it must be located at out microscope eyepiece in order to allow the
measurements of objects being viewed. For stage scale, it is located on another
slide that contain slides.
OBJECTIVE
·
To measure and count cells using a microscope
RESULT
1)
lactobacillus
1)
yeast
400x magnification
|
1000x magnification
|
|||
calibrate
|
Stage
micrometer
|
Ocular
division
|
Stage
micrometer
|
Ocular
divison
|
0.03
mm
|
39
division
|
0.09
mm
|
96
division
|
|
7.69
x10⁻⁴ mm
|
1
division
|
9.38x10⁻⁴ mm
|
1
division
|
|
0.769
µm
|
1
division
|
0.94
µm
|
1
division
|
|
400x
magnification
4 division x 0.769 µm
=3.076 µm
1000x
magnification
7 division x 0.94 µm
= 6.58 µm
LACTOBACILLUS :
400x
magnification
2 division x 0.769 µm
=1.538 µm
1000x
magnification
5 division x 0.94 µm
=4.7 µm
DISCUSSION
How to Use Ocular Micrometer
1)
Put the stage micrometer on the stage and focus
the microscope by using the lowest power
objective in order to get the observed image is superimposed on the eyepiece
scale.
2)
Count the divisions of the eyepiece scale that
correspond top of definite number of divisions on the stage scale.
3)
The measurement of an eyepiece division in
micrometer (µm)
is calculated.
4)
Repeat the above steps by using the high-power
and oil immersion objective.
For the using of ocular micrometer, first of all, it must be
calibrated. In order to make scale sharply, adjust the focus of the eyepiece
and also adjust the other eyepiece to match the focus. Stage micrometer is used
to calibrate any ocular scale. A stage micrometer scale is simply a microscope
slide with the scale on the surface. A typical micrometer scale is 2mm long and
at least part of it should be etched with divisions of 0.01mm (10µm).
Suppose that a stage micrometer scale has divisions that are equal
to 0.1 mm, which is 100 micrometers (µm). Suppose that the scale is lined up
with the ocular scale, and at 100x it is observed that each micrometer division
covers the same distance as 10 ocular divisions. Then one ocular division
(smallest increment on the scale) = 10 µm at 100 power. The conversion to other
magnifications is accomplished by factoring in the difference in magnification.
In the example, the calibration would be 25 µm at 40x, 2.5 µm at 400x, and 1 µm
at 1000x.Some stage micrometers are finely divided only at one end. These are
particularly useful for determining the diameter of a microscope field. One of
the larger divisions is positioned at one edge of the field of view, so that
the fine part of the scale ovelaps the opposite side. The field diameter can
then be determined to the maximum available precision.
CONCLUSION
The correct way to calibrate the ocular micrometer has been
explained. Ocular micrometer has a ruler that allows the user to measure the
size of magnified specimens. Besides, through these experiment, it has shown on
how to calculate the scale using stage scale and ocular eyepiece. By using the
ocular micrometer, microorganisms or cell can be measured and compared as well.
REFERENCE
NEUBAUER
CHAMBER
INTRODUCTION
Neubauer Chamber was
invented by Louis-Charles Malassez and consists of a heavy glass slide with a rectangular indentation that
creates a chamber. This chamber is engraved with a laser-etched grid of perpendicular lines. The device is carefully
crafted so that the area bounded by the lines is known, and the depth of the
chamber is also known. It is therefore possible to count the number of cells or
particles in a specific volume of fluid, and thereby calculate the
concentration of cells in the fluid overall.
RESULT
 |
Figure 1 : 400x magnification
|
Result from the experiment is as shown below :
390 ÷ 10 = 39
Volume
= 0.02 x 0.02 x 0.01 mm
= 4 x 10⁻3 mm
= 4 x 10⁻6 cm
= 4 x 10-6 ml
1ml
= 39 ÷ (4 x 10-6 )
= 9.75 x 10-5 cells/ml
3 x
0.01 = 0.03 nm
39
divisions = 0.03 ÷ 39
= 7.69 x 10-4 mm
per division
= 0.769 µm per division
DISCUSSION
A device used for determining the number of cells per unit volume
of a suspension is called a counting chamber. The most widely used type of
chamber is called a hemocytometer, since it was originally designed for
performing blood cell counts.
CONCLUSION
This report has identified how to use the Neubauer Chamber. This special chamber is a heavy glass slide with two counting areas separated by a H-shaped trough. A special coverslip is placed over the counting areas. When the slide observed via microscope, the sample was viewed on the many grids. These grids helps to count the cells under the microscope.
REFERENCE
http://www.google.com.my/imgres?q=what+is+neubauer+chamber&hl=en&sa=X&biw=1280&bih=675&tbm=isch&prmd=imvns&tbnid=OtkFiUrk1OmgXM:&imgrefurl=http://en.wikipedia.org/wiki/File:Neubauer_improved_counting_chamber.jpg&docid=3uw5V8ivfrtQrM&imgurl=http://upload.wikimedia.org/wikipedia/commons/4/4d/Neubauer_improved_counting_chamber.jpg&w=2331&h=955&ei=WaR9T9LAJIXorQfVyN3cDA&zoom=1
http://en.wikipedia.org/wiki/Hemocytometer
http://sfiles.crg.es/protocols/ http://www.ruf.rice.edu/~bioslabs/methods/microscopy/cellcounting.htmlcellculture/img/neubauer.jpg/view
No comments:
Post a Comment