A fertile domain for nanoscience

Since Democritus first proposed the hypothesis that matter was comprised of indivisible 'atoms', the concept of the atom has been constantly re-invented. In the early twentieth century the 'plum pudding' description of atomic structure as a sphere packed with 'currants' of positive and negative charge was replaced by a structure largely comprised of empty space with orbitals of electrons surrounding a nucleus of positive and neutral particles. In 1937 a group of investigators at Columbia University demonstrated that not only electrons but even neutrons possess an intrinsic magnetic moment [1]. Introducing a magnetic field on a liquid sample such as water, in which the nuclear magnetic moments of the protons are randomly oriented, causes a tiny surplus of the moments to become aligned parallel with the applied field. When this field is removed the sample releases a detectable signal. Nowadays such magnetic resonance effects are routinely used in medical imaging and diagnostics, and constitute a field of fruitful activity in nanotechnology research.