2. Topics  What is glass  Why glass breaks  Chemically strengthened glass how it works make at home?  Tempered glass  Laminated glass  Special types

3. (Regular) glass  Used everywhere  Main compounds: Silicon dioxide (SiO 2 ) Sodium oxide (Na 2 O Sodium carbonate (Na 2 CO 3 )  Brittle

4. Why glass breaks?  Compression X Tension  Microscopic defects

5. Chemically strengthened glass  Regular glass bathed in salt(s) Sodium atoms -> potassium atoms  Only thin surface is treated

6. Chemically strengthened glass  Constant compression  Higher force to break  Flexible

7. Gorilla glass  Commercial brand  Smartphones, tablets…  Patented chemical mix, process (temperatures) …

8. Try it at home?  2hours+  400°C  Molten KNO3 Strength increase: 3-4 times Youtube channel „Applied science“

9. Unbreakable?  Nope…

10. Tempered glass  Thermal process Surface rapidly cooled  6 times stronger  Shatters into small pieces good/bad?

11. Laminated glass  Glass+glue+glass Stays together  Safety/security feature Skyscraper windows Windshields …  Soud isolation

12. Fused quartz/silica glass  No added ingredients – pure SiO 2  High temperature (2000°C) Halogen bulbs  UV transparent  Special applications

13. Sugar glass  Easy to break  Used in movies or food decorations  Molten sugar+water+corn syrup

14. Questions?  Every application needs another type  Glass looks trivial but is it?  Questions?