The image to the left shows patterns formed by silicon as it solidifies from a molten state. Silicon is melted by passing an electrical current through a piece of silicon wafer; when the current is turned off, the silicon rapidly cools, solidifying into crystalline structures. Imaged through a scanning electron microscope, the branches of the 'snowflake' are approximately 5 microns long, about one-tenth the width of a human hair.

This image shows a structure of aligned carbon nanotubes, grown on a silicon substrate that was seeded with iron particles and placed in a high-temperature oven filled with a hydrocarbon gas. The carbon nanotubes self-assembled during growth, forming a structure containing thousands of nanotubes in parallel. Imaged through a scanning electron microscope, the 'scroll' is approximately 50 microns in diameter, about the width of a human hair.

The nanostructures were fabricated and imaged by Anastasios John Hart SM '02, PhD '06 (http://www.nanobliss.com).

Cover designs by Wing-Ip Ngan.