About the Cover:

Celebrating Einstein. On April 5, 1921, Albert Einstein rode in a motorcade after being greeted by Mayor Hylan and other dignitaries at New York City Hall in ceremonies befitting a chief of state. It was his first visit to the United States. In the afternoon that day, he lectured to an invitation-only audience of 500 in the rotunda of Low Memorial Library at Columbia University on the theory of relativity. In 1905, Einstein published work that spawned a revolution in physics, and the centennial anniversary of his &ldqquo;miraculous year&rdqquo; is celebrated with articles throughout this issue.

• Einstein Revisited
• The Physics Teacher: Black Boxes, Frozen Lakes, and What = mc²?
• E = mc² for the Chemist: When Is Mass Conserved?
• Displacements of Brownian Particles in Terms of Marian von Smoluchowski's Heuristic Model
• A Safer, Easier, Faster Synthesis for CdSe Quantum Dot Nanocrystals
• Quantum Dots: An Experiment for Physical or Materials Chemistry
• Relativistic Effects and the Chemistry of the Heaviest Main-Group Elements