IntroductiontotheMicroscopeandScientificDrawings
After completing this laboratory, you should be able to perform the following:
1. Mount and stain a specimen on a slide and prepare it for microscope viewing.
2. Identify parts of a compound microscope and operate it effectively.
3. Make proper biological drawings of both and an animal and plant cell.
CalculatingFieldDiameterMeasurement
1) Set the magnification to the lowest setting (4X)
Eqn.#1CalculatingMagnification:
TOTALMAGNIFICATION=OCULARLENSXOBJECTIVELENS
40X
=
10X
X
4X
2) Use the ruler provided to measure the width of the field of view (field diameter). Line up the ruler on
the center of the stage so that the scale is visible through the microscope. Then, line up the 0 mm
vertical line with the left side of the circular field of view. At the highest magnification you might
have to estimate. Complete the chart below.
Magnification
40X
100X
Field Diameter (mm)
Field Diameter (µm)
3) Now turn the 40X objective into place. You will observe the field of view in less than 1 mm. Instead
of measuring the field directly it is more accurate to calculate the diameter by the following equation:
Eqn.#2CalculatingFieldDiameter:
(HIGH-POWERFIELDDIAMETERµm)=(LOW-POWERMAGNIFICATION)
(LOW-POWERFIELDDIAMETERµm)(HIGH-POWERMAGNIFICATION)
Complete the chart below.
Magnification
400X
Field Diameter (mm)
Field Diameter (µm)
Eqn.#3CalculatingActualSize:
ACTUALSIZE=__________FIELDDIAMETER(µm)_____________
#OFTIMESSPECIMENFITSACROSSDIAMETER
Eqn.#4CalculatingScale(DrawingMagnification:
SCALE=MEASUREDSIZEOFDRAWING(µm)
ACTUALSIZEOFSPECIMEN(µm)
Tofindthescaleofyourdrawing,determine:
1.Measuredsize:Decidewhichdimensionofyourcompletedbiologicaldiagramyouwillmeasure,andusethisinthenumeratorofequation#4.
2.ActualSize:Useequation#3,andsubstitutethisvalueintothedenominatorofequation#4.
HelpfulHints:
-ScaleisexpressedasaratioofthemeasuredsizetoONEunitoftheactualsize.Scale,likeratio,hasNOUNITS.Ex.Scale=200:1
-AlwayscompareLIKEdimensions.i.e.,iftheverticaldimensionistakentomeasurethesizeofthedrawing,alsousethevertical
dimensiontodeterminetheactualsizeoftheobject.
CommandmentsofDrawingBiologicalDiagrams
One of the most important skills a biologist can have is keen observation. A second is
communicating what they have seen. Biological diagrams should record the main
features of a specimen. They should show sufficient cellular detail and accurate
proportions. Making accurate diagrams ensures careful observations.
Biological diagrams should:
• Be drawn on BLANK PAPER
• Be drawn neatly with a sharp hard
pencil
• Have a PAGE HEADING which
identifies the name of the lab
• Have a TITLE which identifies the
diagram
• Be drawn with neat, clean, SINGLE,
CONTINUOUS lines (do not use thick,
sketchy lines)
• Do not colour or shade. Thickness
should be shown with a double line
and density differences with stippling
• Be at least HALF a page in size.
• Be placed to the LEFT 2/3 of the page
• Include neatly PRINTED and correctly
spelled labels one UNDERNEATH the
other on the RIGHT side of the page
• Include label lines drawn with a RULER
• Include the following information:
Page Heading, Title, Name, Date,
Scale, Magnification, Stain.
Name:_______
Date:________
PageHeading–EukaryoticCell
Title–LiverCell
Example of Biological Diagram:
Scale:
Magnifica
EukaryoticCellLab
Part1:ObservingPlant(onion)
1.
2.
3.
4.
Prepareawetmountbygentlyremovingathinlayeroftheonionskin
Placetheskinontheglassslide,add1dropofiodinetostainthecells
Gentlyplaceacoverslipoveryourspecimen
Drawoneonioncellunderhighpowerbelow
Besuretoidentifythenucleus,cellwall,cellmembrane,andcytoplasmonyourdrawing.
REMINDER:recordthenumberoffitsunderhighpower__________________
Part2:ObservingAnimal(cheek)
5.
6.
7.
8.
Bygentlyscrapingtheinsideofyourcheekwithatoothpickprepareawetmount
Smearthetoothpickontheglassslide,add1dropofmethylenebluetostainthecells
Gentlyplaceacoverslipoveryourspecimen
Drawonecheekcellunderhighpowerbelow
Besuretoidentifythenucleus,cellmembrane,andcytoplasmonyourdrawing.
REMINDER:recordthenumberoffitsunderhighpower__________________
Part3:BiologicalDiagramandScale
Usingtheroughdrawingscreatedinthislabcompletethefollowing.
1. Onaseparatepieceofblankpaperdrawabiologicaldiagramofarepresentativeeukaryoticcell
(onionorcheek).Yourdiagrammustadheretothe“Commandmentsofbiologicaldiagrams”.
2.Calculatethescaleofyourdrawing.Showallworkonthebackofthediagramincludinghowyou
calculatedHPFDandActualSize.
Microscope&BiologicalAssignment
Intro to Microscopy
1. Pre-lab assignment.
[K6]
2. Calculating High Power Field Diameter.
[K3]
Drawing Biological Diagrams
1. Draw a Biological Diagrams of your stained cheek cell or onion cell.
[C10]
2. Calculating High Power Field Diameter, Actual Size and Scale.
[T8]
Communication
Knowledge
Thinking
/[10]
/[9]
/[8]