1. SNOWFLAKES Nano at its coolest!

2. What do you know about snow?

3. What do you wonder about snow?

4. Outline When does it snow? Why do snowflakes have six sides? Is every snowflake different?

5. When does it snow?

6. It snows when… It’s cold (below freezing) It’s cloudy (water vapor in the air)

9. Why do snowflakes have six sides?

10. Nano is very, very small A nanometer is a billionth of a meter. Molecules are nanometers across.

11. Snowflakes are nano! Nanoscience is nature and technology. Water molecules form ice crystals.

12. Shape is determined by molecular structure Basic shapes of snowflakes Molecular structure of ice crystals

13. Is every snowflake different?

14. Snowflakes have many shapes

15. Type depends on temperature and humidity

20. Snowflakes self-assemble Molecules and cells form themselves into structures… …under the right conditions, with the right raw materials.

21. Snowflakes and nano, in the future New ways to build tiny, nano-sized structures

22. Snowflakes and nano, right now! Ice crystals self-assemble inside the museum

23. Review When does it snow? –Cold, cloudy conditions Why do snowflakes have six sides? –Molecular structure of ice crystals Is every snowflake different? –Temperature and humidity

24. Image sources Courtesy of Kenneth Libbrecht, www.snowcrystals.com

25. Image sources (continued) iStockphoto.com Courtesy of NOAA National Weather Service Collection Courtesy of NASA Marshall Space Flight Center Courtesy of IBM

26. This project was supported by the National Science Foundation under Grant No. ESI-0532536. Any opinions, findings, and conclusions or recommendations are those of the author and do not necessarily reflect the views of the Foundation.