1. Structure & Properties of Solids Understanding the structural and bonding characteristics of substances in the solid phase – “materials science”

4. Composite Materials A material composed of two or more distinct materials that remain separate from each other in the solid phase

6. Four types of solid structures we will explore: • Ionic Crystals • Metallic Crystals • Molecular Crystals • Covalent Network Crystals

7. Ionic Crystals • Form when metal reacts with non-metal • Composed of oppositely charged ions; electrostatically attracted to each other

8. Metallic Crystals • Metal atoms only • Bound by a “sea of electrons”; creating overall region of negative charge explains metallic properties

11. Molecular Crystals • Composed of individual molecules held together by intermolecular forces • Properties vary depending on intermolecular forces present

12. Covalent Network Crystals • Atoms form covalent bonds in an inter-woven network • Properties: • Hardness • Non-conductor • High melting point

13. http://www.youtube.com/watch?v=ndJlgTkm0oQ

14. When heated beyond it’s MP, then cooled quickly, SiO2 changes from a) “sand” to b) “glass” SiO2 glass can be strengthened by adding B2O3, used in lab and kitchen glassware (Pyrex)

15. Semiconductors Type of covalent network solid (containing Si or Ge atoms) A substance that conducts a slight electric current at room temperature A slight increase in temperature causes a significant increase in conductivity www.youtube.com/watch?v=u3GdpbKTPQQ

16. Future of Materials Science • 3D Printing • CNN: http://www.youtube.com/watch?v=e0rYO5YI7kA • Deeper explanation: http://www.youtube.com/watch?v=X5AZzOw7FwA