1. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein 1

2. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein Introduction Optical instrument Lens or combination of lenses Magnify, resolve fine details Earliest methods for examining physical evidence Magnified image = virtual image Image viewed directly = real image. 2

3. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Compound Microscope 3

4. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Compound Microscope Schematic diagram of stereoscopic microscope Two separate monocular microscopes Each has own set of lenses except for the lowest Objective lens common to both microscopes 4

5. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Compound Microscope The Mechanical System Base: the support. Arm: the C-shaped upright structure Stage: the plate on which the specimens are placed Body Tube: the hollow tube on which the objectives and eyepiece lenses are mounted 5

6. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Compound Microscope The Mechanical System Coarse Adjustment: the knob used to focus the microscope lenses by moving the body tube Fine Adjustment: the knob also used to focus the lenses by moving the body tube, but by a much smaller magnitude 6

7. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Compound Microscope The Optical System Illuminator: artificial light, usually supplied by a light bulb, to illuminate the specimen. Transmitted Illumination: when the light is directed up through the specimen from the base. Vertical or Reflected Illumination: when the light comes from above and reflects off the specimen. 7

8. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Comparison Microscope Two independent objective lenses joined together by an optical bridge to a common eyepiece lens. The objects under investigation are observed side-by-side in a circular field that is equally divided into two parts Modern firearms examination Began with the introduction of the comparison microscope Ability to give the firearms examiner a side-by- side magnified view of bullets 8

9. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Stereoscopic Microscope Two monocular compound microscopes Three-dimensional image of a specimen Use both eyepiece lenses Evidence not requiring very high magnification (10x–125x) Large working distance Microscopic examination of big, bulky items 9

10. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein Polarizing Microscopy Plane-polarized Light that is confined to a single plane of vibration Polarizing microscope Examination of the interaction of plane- polarized light with matter 10

11. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein Polarizing Microscopy Wide applications for the study of birefringent materials Materials that split a beam of light in two Each with its own refractive index value Determination of these refractive index data Provides information that helps to identify minerals present in a soil sample or the identity of a man-made fiber. 11

12. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Microspectrophotometer Spectrophotometer coupled with a light microscope. Can simultaneously obtain the visible absorption spectrum or IR spectrum of the material being observed Trace evidence, paint, fiber, and ink evidence. 12

13. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Microspectrophotometer 13

14. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Microspectrophotometer 14

15. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein The Scanning Electron Microscope (SEM) bombards a specimen with a beam of electrons instead of light Produces a highly magnified image from 100x to 100,0000 Depth of focus 300X better than optical systems at similar magnification Bombardment of the specimen’s surface with electrons Produces x-ray emissions Characterize elements present in the material under investigation 15

16. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein Dental Plaque 16

17. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein Bread Mold Aspergillus sp.) 17

18. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein Penecillium sp. 18

19. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein SEM: Hair and Hair follocles 19

20. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein SEM: hafnium nitride interface coating on carbon fibers 20

21. 7- PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458 CRIMINALISTICS An Introduction to Forensic Science, 9/E By Richard Saferstein Dust Mite Family Reunion 21