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•Scientific tools and techniques enable Biologists to probe deeper into the secretes of life
BIG IDEA
One of the most widely used tools in Biology is the Microscope.
WHAT DOES A MICROSCOPE DO?• Enlarges an image as well as shows
detail. • Magnification-the amount an object’s size
is increased• Resolution-the power to show details
clearly• Microscopes vary in powers of magnification
and resolution.
TOOLS OF THE TRADE: MICROSCOPES
*Compound Light Microscope
A Compound microscope has a series of lenses to collect and focus the light transmitted through the specimen mounted on a glass slide
•Must be thinly sliced or very small
•Pair of lenseso Ocular lens (eye piece)o Objective lens (nose piece)
•Magnification determined by multiplying power of both lenses
o Eyepiece 10X times Objective power (10X, 20X, 40X…)
•Highest Maximum magnification is around 1000X•Can be used to study LIVE specimens
LIGHT MICROSCOPES
*Transmission Electron Microscope (TEM)•Uses a beam of electrons to produce an enlarged image of very thinly sliced specimen on screen or photographic plate•Image focused by magnetic lenses•200,000X magnification•Cannot be used to view living specimens
ELECTRON MICROSCOPES
*Scanning Electron Microscope (SEM)
•3D image•Specimens not sliced for viewing•Surface sprayed with fine metal coating•Also uses electron beam and fluorescent screen or photographic plates•100,000X magnification•Cannot be used to view living specimens
ELECTRON MICROSCOPES
Body Tube
Ocular Lens
Revolving Nosepiece
Objective lens
Objective lens
Objective lens
Stage Clips
Diaphragm
Light source
Arm
Stage
Course Focus / Adjustment
Fine Focus / Adjustment
Base
The International System of Measurement, or SI is the one
system of measurements scientists use.
ALSO KNOWN AS:The Metric System
Tools of the trade
The Metric System– Uses Base Units
• Describes what you are measuring.» Length-meter (m)» Volume-liter (L)» Mass-gram (g)» Temperature-Celsius (C)» Time-second (s)
Tools of the trade
BASE UNIT MEASURES
Meter Length
Liter Volume
Gram Mass
The Metric System• Major advantages:
– It is a decimal system based on multiples or fractions of 10’s
– Commonly used among all scientists– Easy to convert between unit prefixes:
– Kilo – 1000– Deci – 1/10th – Centi – 1/100th
– Milli – 1/1,000th – Micro – 1/1,000,000th …of the base UNIT
Tools of the trade
In SI, prefixes are added to the base unit to signify the value.•Prefixes are multiples of 10…
•For example:1 kilogram = 1000 grams•1 centimeter = 1/100th of a meter•1 milliliter is 1/1000th of a liter, or 1000 X smaller than a liter
TOOLS OF THE TRADEPREFIX …PLUS BASE UNIT
Kilo – 1/1000th Kilo+gram = Kilogram
Hecto – 1/100th Hecto+liter = hectoliter
Deka – 1/10th Deka+gram = dekagram
Deci - 10 Deci+liter = deciliter
Centi - 100 Centi+meter = centimeter
Milli - 1000 Milli+meter = milliliter
The SI System makes conversions easier!
•1 mile=1760 yards=5280 feet= 63,360 inches – Ugh!!•Because all of the unit relationships in the metric system are based on multiples of 10, it is easy to convert between prefix units - just multiply or divide by 10!•100,000 cm = 1000 meters = 1 kilometer•1 kilometer = 1000 meters = 100,000 cm
TOOLS OF THE TRADE
For example:• Centimeters are 10 times larger than
millimetersSo..• 1 centimeter = 10 millimeters
1 10 100 1000.10.01.001
Kilo- Hecto- Deka-BASE UNITMeterGramliter
Deci- Centi- Milli-
Tools of the trade
US Conversions within theMetric System
TOOLS OF THE TRADE
Mass vs. Weight(Not the same!)
Mass-How much matter (particles) you are made of.Weight-How much gravity pulls on you.
A QUICK SIDE NOTE…