Microscopy and Microscopy and MeasurementMeasurement

Section 1.4Section 1.4

MicroscopesMicroscopes

► Instruments that produce an enlarged Instruments that produce an enlarged image of an objectimage of an object

►First used in the 1600’sFirst used in the 1600’s

►MagnificationMagnification: the increase in an : the increase in an object’s apparent sizeobject’s apparent size

►ResolutionResolution: the power to show details : the power to show details clearlyclearly

Light MicroscopesLight Microscopes

►Compound light microscope (LM):Compound light microscope (LM): produces images by focusing light rays produces images by focusing light rays through a specimen mounted on a through a specimen mounted on a glass slideglass slide

►Specimen must either be very small or Specimen must either be very small or be sliced thin enough to be be sliced thin enough to be transparenttransparent

Onion CellsOnion Cells

Parts of a Compound Light Parts of a Compound Light MicroscopeMicroscope

►StageStage: the place where the slide rests: the place where the slide rests►Stage clipsStage clips: hold the slide in place: hold the slide in place

►Objective lensObjective lens: enlarges the image: enlarges the image►Ocular lensOcular lens: projects image through : projects image through

eyepieceeyepiece

Power of MagnificationPower of Magnification

►Refers to how much a specimen is Refers to how much a specimen is magnified magnified

►Example: 40X means the image is Example: 40X means the image is enlarged 40 times the actual size of enlarged 40 times the actual size of the specimenthe specimen

Electron MicroscopeElectron Microscope

►A beam of A beam of electrons electrons produces an produces an enlarged image of enlarged image of the specimenthe specimen

►Much more Much more powerful than powerful than light microscopeslight microscopes

Scanning Electron Microscope Scanning Electron Microscope (SEM)(SEM)

►3-D images3-D images

►Specimen is sprayed with a fine metal Specimen is sprayed with a fine metal coating then a beam of electrons is coating then a beam of electrons is passed over the surfacepassed over the surface

►The electrons are projected onto a The electrons are projected onto a photographic plate producing an imagephotographic plate producing an image

SEM ImagesSEM Images

Transmission Electron Transmission Electron Microscope (TEM)Microscope (TEM)

►Transmits a beam of electrons through Transmits a beam of electrons through a very thinly sliced specimena very thinly sliced specimen

►Magnetic lenses enlarge the image Magnetic lenses enlarge the image and focus it on a photographic plateand focus it on a photographic plate

►Can magnify objects up to 200,000XCan magnify objects up to 200,000X

TEM ImagesTEM Images

MeasurementMeasurement

►SI: international System of SI: international System of MeasurementsMeasurements

►SI units are universally understood and SI units are universally understood and accepted by scientistsaccepted by scientists

►Seven base unitsSeven base units

Some SI PrefixesSome SI Prefixes

►Prefix abbreviation factor of base Prefix abbreviation factor of base unit unit

giga G 1,000,000,000giga G 1,000,000,000

mega M 1,000,000mega M 1,000,000

kilo k 1,000kilo k 1,000

hecto h 100hecto h 100

deka da 10 deka da 10

►Prefix abbreviation factor of base unitPrefix abbreviation factor of base unit

deci d 0.1deci d 0.1

centi c 0.01centi c 0.01

milli m 0.001milli m 0.001

micro micro ЛЛ 0.000001 0.000001

nano n 0.000000001 nano n 0.000000001

pico p 0.000000000001 pico p 0.000000000001

Derived UnitsDerived Units

► Produced by the Produced by the mathematical mathematical relationship between relationship between two base units two base units

► Examples: area, Examples: area, volume, mass volume, mass density, specific density, specific volume, Celsius volume, Celsius temperaturetemperature

DensityDensity

►Density = mass/volumeDensity = mass/volume

D = m/vD = m/v

Study for Test!Study for Test!

► Make sure to:Make sure to:

1.1. Read the chapterRead the chapter

2.2. Make flashcards of the vocabMake flashcards of the vocab

3.3. Learn the vocab terms and definitionsLearn the vocab terms and definitions

4.4. Take good notesTake good notes

5.5. Do section and chapter review questionsDo section and chapter review questions

6.6. Spend at least 15 minutes a night Spend at least 15 minutes a night studyingstudying