SNOWFLAKES
Nano at its coolest!
What do you know
about snow?
What do you wonder
about snow?
Outline
• When does it snow?
• Why do snowflakes have six sides?
• Is every snowflake different?
When does it snow?
It snows when…
• It’s cold (below freezing)
• It’s cloudy (water vapor in the air)
Why do snowflakes
have six sides?
Nano is very, very small
• A nanometer is a billionth of a meter.
• Molecules are nanometers across.
Snowflakes are nano!
• Nanoscience is nature and technology.
• Water molecules form ice crystals.
Shape is determined by
molecular structure
Basic shapes
of snowflakes
Molecular structure
of ice crystals
Is every snowflake
different?
Snowflakes have many shapes
Type depends on
temperature and humidity
Snowflakes self-assemble
• Molecules and cells form
themselves into structures…
• …under the right conditions, with
the right raw materials.
Snowflakes and nano,
in the future
New ways to build tiny, nano-sized structures
Snowflakes and nano,
right now!
Ice crystals self-assemble
inside the museum
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
Image sources
Courtesy of Kenneth Libbrecht, www.snowcrystals.com
Image sources (continued)
iStockphoto.com
Courtesy of NOAA National Weather Service Collection
Courtesy of NASA Marshall Space Flight Center
Courtesy of IBM
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.