1. Section 1.4 Tools and Techniques of Biology
Biology Honors
Section 1.4 Tools and Techniques of Biology

2. Compound Light Microscope
Shines light through a specimen
2 lenses magnify an image
Specimens must be thin- single celled organisms or multicellular organisms sliced thin

3. Eyepiece/Ocular Lens
Magnifies image 10X

4. Objective Lens Enlarges image Three types of objective lens (on ours)
Scanning: Magnification X4
Low Power: Magnification X10
High Power: Magnification X40

5. Nosepiece
Rotating structure attaching objective lenses above the specimen

6. Stage Platform that supports slide Moves up and down with coarse
and fine adjustment knobs
Often has stage clips

7. Light Source
Light bulb
Some microscopes use mirrors to direct light

8. Magnification Increase of an object’s apparent size
Determined by power of the ocular lens X objective lens
Example: Ocular lens is 10X and scanning objective is 4X
Total magnification is 40X

9. Resolution Power to show details clearly in an image
Light microscopes have limited resolution
Electron microscopes have higher resolution

10. Electron Microscope
Uses a beam of electrons to magnify an image (not light)
Images are always black and white
Not for viewing live organisms
Electrons have a wavelength 100,000 times smaller than visible light

11. Electromagnetic Spectrum

12. Scanning Electron Microscope
SEM
Electron beam passes over surface of 3-D object creating 3-D images

13. Transmission Electron Microscope
Transmits electrons through a thinly sliced specimen
(use diamond knives to cut thin enough sections)
Magnify objects up to 200,000 times

14. Units of Measurement
Need a common measurement system to compare results
Système International d’Unités (SI)
Based on the metric system

15. Metric System Decimal system based on powers of 10
Base Units: describe length, mass, time, and other quantities
Multiples of base units designated by prefixes
Base Quantity
Name
Abbreviation
Length
Meter m
Mass
Kilogram kg
Time
Second s
Electric current
Ampere A
Thermodynamic temperature
Kelvin K
Amount of substance
Mole
mol
Luminous (light) intensity
Candela cd

16. Metric Unit Prefixes Text Symbol Factor Tera T 1,000,000,000,000 Giga
Mega M
1,000,000
Kilo k
1,000
Hecto h
100
None 1
Deci d
0.1
Centi c
0.01
Mili m
0.001
Micro
0.000,001
Nano n
0.000,000,001
Pico p
0.000,000,000,001

17. Metric Staircase
Chart from

18. Derived units Base units can’t be applied to area or volume
Quantity
Name
Abbreviation
Area
Square meter m2
Volume
Cubic meter m3
Density
Kilogram per cubic meter
kg/m3
Specific volume
Cubic meter per kilogram
m3/kg
Celsius temperature
Degree Celsius °C
Time
Minute
1 min = 60 sec
Hour
1 h = 60 min
Day
1 day = 24 h
Liter
1 L = 1,000 cm3
Mass
Kilogram metric ton
1,000 g = 1 kg
1 t = 1,0000 kg
Base units can’t be applied to area or volume
Mathematical relationship between two base units or two derived units

19. Powers of 10- Just how big or small are things?
Powers of 10 video 1977
Scale of the Universe tool

20. Accuracy
Degree of closeness of a measurement of a quantity to that quantity’s actual value
Nearness of a calculation to the actual value

21. Precision
The degree to which repeated measurements of the same quantity under unchanged conditions show the same results
Resolution of the representation
Defined by the number of decimals

22. Valid Experimental designs
Must have both Accuracy and Precision!
Invalid measurements could be accurate, but not precise; precise but not accurate; or both
Systematic errors- increasing sample size improves precision (repeated measurements), but not necessarily accuracy (numbers might still be off- misrepresenting the actual value)

23. Triple-beam Balance Measures mass Must be zeroed to begin
Add up values on all beams to find final mass of object
Estimate last value (nearest 100th of gram)
Reading a triple beam balance

24. Graduated Cylinder Measures volume of liquid in mL
Can be used in displacement to find volume of a solid
Estimate last value (measure to nearest 10th of mL)
Look at the Bottom of the meniscus (curve)
Reading a Graduated Cylinder

25. Ruler Measures length Estimate last value
Image from

26. Thermometer Measure temperature SI unit is Kelvin
We will measure in °C
Estimate last value

27. Additional tools of biology
Beaker
Test tube holders
Dropper/pipette
Beaker tongs
Erlenmeyer Flask
Hot plate
Florence Flask
Bunsen Burner
Funnel
Stirring rod
Ring stand and clamps
Test tubes and rack

28. Beakers
Used for mixing, holding, and estimating liquid volume

29. Droppers/Pipettes
A dropper is used to transfer a small volume of liquid (less than one mL).
On top of each dropper is a “rubber bulb”
DO NOT PUT LIQUID IN THE RUBBER BULB!

30. Erlenmeyer flask Storing and heating liquids.
Especially useful for capturing vapors or fumes- can be used with a stopper and glass tubing

31. Florence flask Evenly heating liquids
Can also be used with a stopper and glass tubing

32. Funnel
Pouring substances without spilling.

33. Goggles
Eye protection

34. Ring stand and clamp
Holding equipment while heating.

35. Stirring rods
Stir solutions

36. Test tubes and rack
Test tubes hold substances.
Rack holds test tubes

37. Hot Plate
Heating substances with electricity

38. Bunsen Burner
Heat substances with a flame