The imperfection of strontium titanate

When you squeeze some crystals, you distort their lattice of atoms just enough to separate a pair of charged particles and that in turn gives rise to a voltage. Such materials are called piezoelectric crystals. Not all crystals are piezoelectric because the property depends on what the arrangement of atoms in the lattice is. For … Read more

The symmetry incarnations

This post was originally published on October 6, 2012. I recently rediscovered it and decided to republish it with a few updates. Geometric symmetry in nature is often a sign of unperturbedness, as if nothing has interfered with a natural process and that its effects at each step are simply scaled-up or scaled-down versions of … Read more

The Symmetry Incarnations – Part I

Symmetry in nature is a sign of unperturbedness. It means nothing has interfered with a natural process, and that its effects at each step are simply scaled-up or scaled-down versions of each other. For this reason, symmetry is aesthetically pleasing, and often beautiful. Consider, for instance, faces. Symmetry of facial features about the central vertical … Read more