1. Microscopes

2. Tools of a Biologist Light Microscopes: –Simple Microscope (Single Lens- Magnifying Glass (1600s) –Inventor:

3. Tools of a Biologist –Compound Microscope (2 lenses) –Robert Hooke (1600s)

4. Modern Compound Light Microscope PARTS

6. Field of View

7. Depth of Focus

8. Tissue Prep for Microscopy 1. Fixation 2. Embed in wax 3. Slice with Microtome, Mount on slide, Stain

9. Stains Help visualize details of specimen –Vital Stains=Don’t harm living specimens (ex. Methyl Blue) –Lethal Stains=Kills Specimen (ex. Iodine)

10. Tissue Prep Center Embedding Area Microtome Water bath with sliced wax/tissue

11. Tissue prep-Mount onto slides

12. How does a lens work?

13. Can’t see virtual images unless you look through a lens Virtual vs. Real Images

14. Magnifying Lens Virtual Lens

15. Real images can be seen directly without a lens -like those seen on a movie screen

16. Microscopes in Forensic Science Compound Comparison Stereoscopic Polarizing Microspectrophotometer Scanning Electron Microscope

17. Stereoscopic Microscope 10x-125X 3D Image Right-side-up image Most frequently used in crime lab Wide field of view Great depth of focus Large working distance

18. Cheek Cells using Phase-Contrast Microscope No Stains Needed Can view live specimens

19. Scanning Electron Microscope 100,000X Magnification Can’t view live organisms 3D Image Blast electrons at object

20. Red Blood Cells using a SEM

24. Application Gunshot Residue

25. Collect Residue

26. Transmission Electron Microscope 2D Image Can’t View live organisms 250,000X Mag Blast electrons at object

27. Gunshot particles

28. SEM Coupled with X-Ray Analysis To Determine Elemental Nature of Residue

29. Blood Cells using a TEM

30. Confocal Laser Microscope

31. Comparison Microscope Compare: Bullets Cartridges Fibers Hairs

33. Polarizing Microscope

34. What’s an everyday use of polarized light?

36. Effect of Polarized Light Analyzing minerals in soil Analyzing synthetic fibers

37. Microspectrophotometer Microscope Spectrophotometer

38. Application

39. Magnification of money to fiber and ink level CounterfeitGenuine

40. Application CounterfeitGenuine Absorbance of light by ink