Ch11

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Ch11

  1. 1. Materials and their Properties Chapter 11 Great Idea: A material’s properties result from its constituent atoms and the arrangements of chemical bonds that hold those atoms together
  2. 2. Chapter Outline <ul><li>Materials and the Modern World </li></ul><ul><li>The Strengths of Materials </li></ul><ul><li>Electrical Properties of Materials </li></ul><ul><li>Magnetic Properties of Materials </li></ul><ul><li>Microchips and the Information Revolution </li></ul>
  3. 3. Materials and the Modern World
  4. 4. Materials and the Modern World <ul><li>Materials define technical sophistication </li></ul><ul><li>Chemists’ contributions </li></ul><ul><li>Properties of materials depend upon: </li></ul><ul><ul><li>The kind of atoms of which it is made </li></ul></ul><ul><ul><li>Arrangement of atoms </li></ul></ul><ul><ul><li>Type of bonding of atoms </li></ul></ul>
  5. 5. Typical Room with High-Tech Materials
  6. 6. The Strengths of Materials
  7. 7. Different Kinds of Strength <ul><li>Strength </li></ul><ul><ul><li>Compressive </li></ul></ul><ul><ul><li>Tensile </li></ul></ul><ul><ul><li>Shear </li></ul></ul><ul><li>Elastic limit </li></ul><ul><li>Strength depends on type and arrangement of bonds </li></ul>
  8. 8. Strength of Muscle Fibers
  9. 9. Strength of Suspension Bridges
  10. 10. Strength of Girder Framework
  11. 11. Strength of a Diamond’s Crystal Structure
  12. 12. Composite Materials <ul><li>Composite materials </li></ul><ul><ul><li>Combination of materials </li></ul></ul><ul><ul><li>Increase strength </li></ul></ul>
  13. 13. Composite Materials
  14. 14. Electrical Properties of Materials
  15. 15. Conductors and Insulators <ul><li>Conductors </li></ul><ul><ul><li>Electrical conductor </li></ul></ul><ul><ul><ul><li>Electrons flow freely </li></ul></ul></ul><ul><ul><li>Electrical resistance </li></ul></ul><ul><ul><ul><li>Draining of energy from current </li></ul></ul></ul><ul><li>Insulators </li></ul><ul><ul><li>No electricity flows through them </li></ul></ul>
  16. 16. Electrical Wiring
  17. 17. Semiconductors <ul><li>Semiconductors </li></ul><ul><ul><li>Neither good conductors nor insulators </li></ul></ul><ul><li>Example: silicon </li></ul><ul><ul><li>Conduction electrons </li></ul></ul><ul><ul><li>Hole </li></ul></ul>
  18. 18. Silicon Crystal
  19. 19. Holes
  20. 20. Superconductors <ul><li>Superconductivity </li></ul><ul><ul><li>Absence of electrical resistance </li></ul></ul><ul><ul><li>At cold temperature electrons move without losing energy </li></ul></ul><ul><li>How? </li></ul><ul><ul><li>Electron-ion interactions </li></ul></ul>
  21. 21. Searching for New Superconductors
  22. 22. Magnetic Properties of Materials
  23. 23. Magnetic Properties of Materials <ul><li>Magnetic field </li></ul><ul><ul><li>Due to electrical current </li></ul></ul><ul><ul><ul><li>Electrons spinning </li></ul></ul></ul><ul><li>Arrangement of atomic magnets </li></ul><ul><ul><li>Determines level of magnetism </li></ul></ul>
  24. 24. Dipole Magnetic Field of Atoms and magnets
  25. 25. Different Magnetic Behaviors
  26. 26. Microchips and the Information Revolution New materials often lead to new technologies that change society
  27. 27. Doped Semiconductors <ul><li>Doping </li></ul><ul><ul><li>Addition of minor impurity </li></ul></ul><ul><li>n -type semiconductor </li></ul><ul><ul><li>Extra electron </li></ul></ul><ul><li>p -type semiconductor </li></ul><ul><ul><li>Hole </li></ul></ul>
  28. 28. n -Type and p -Type Semiconductors
  29. 29. Diodes <ul><li>Diodes </li></ul><ul><ul><li>Combination of p - and n -type semiconductors </li></ul></ul><ul><ul><li>One-way gate </li></ul></ul>
  30. 30. Diodes
  31. 31. Diodes Convert AC to DC
  32. 32. Technology <ul><li>Photovoltaic cells and solar energy </li></ul>
  33. 33. The Transistor <ul><li>Transistor </li></ul><ul><ul><li>Control flow of electrons </li></ul></ul><ul><ul><ul><li>Emitter </li></ul></ul></ul><ul><ul><ul><li>Base </li></ul></ul></ul><ul><ul><ul><li>Collector </li></ul></ul></ul><ul><li>Uses </li></ul><ul><ul><li>Cell phone </li></ul></ul><ul><ul><li>Computer </li></ul></ul>
  34. 34. A pnp and an npn Transistor
  35. 35. A Transistor Acting Like an Amplifier
  36. 36. A Transistor Acting Like a Switch
  37. 37. Microchips <ul><li>Microchip </li></ul><ul><ul><li>Complex array of p - and n -type semiconductors </li></ul></ul><ul><ul><li>Integrated circuit </li></ul></ul><ul><li>Design </li></ul><ul><ul><li>Layers interconnected </li></ul></ul>
  38. 38. Microchip
  39. 39. Technology <ul><li>Jim Trefil give his car a tune-up </li></ul>
  40. 40. Information <ul><li>The binary digit or bit </li></ul><ul><ul><li>Two possible answers to a simple question </li></ul></ul><ul><ul><li>8 bits = 1 byte </li></ul></ul>
  41. 41. Science by the Numbers <ul><li>Is a picture really worth a thousand words? </li></ul>
  42. 42. Computers <ul><li>Computer </li></ul><ul><ul><li>Stores and manipulates information </li></ul></ul><ul><li>Central Processing Unit (CPU) </li></ul><ul><li>Nanotechnology </li></ul>
  43. 43. Old and New Computer Game Technology
  44. 44. The Science of Life <ul><li>The computer and the brain </li></ul>

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