Convert Fathom (fath) to Picometer (pm) instantly.
About these units
Fathom (fath)
A fathom is equal to 6 feet and is historically associated with maritime measurement. Its origins may lie in the approximate span of a fully outstretched human arms, which was convenient for measuring rope lengths by hand aboard ships. Sailors used the fathom to estimate water depth through weighted lines, giving rise to the practice of "sounding" the depths. The fathom became a cornerstone unit in nautical life because it fits the human scale while also being large enough to measure significant underwater distances. Charts, sonar readings, and older depth gauges frequently utilized fathoms, although modern equipment increasingly displays depths in meters. Still, many mariners—particularly in regions using imperial measurements—continue to think instinctively in fathoms when estimating safe anchoring or navigating shallow waters. The unit persists as an important piece of maritime history and remains in active use by traditional sailors, divers, and some fishing industries. Its survival reflects the enduring cultural heritage of nautical practice.
Picometer (pm)
At 10⁻¹² meters, the picometer occupies a scale close to the dimensions of atoms but slightly finer than typical atomic radii. Chemists use picometers to express covalent bond lengths, ionic radii, and atomic radii. For example, the radius of a hydrogen atom is about 53 pm. The unit also appears frequently in crystallography, where X-ray diffraction reveals lattice spacing on the order of a few hundred picometers. The picometer provides a numeric convenience: atomic structures are neither too large nor too small to measure accurately in this unit. In physics, picometer-scale distances become relevant when examining the interactions of electrons in tightly bound orbitals or in high-resolution measurements of electric dipole moments. It is a unit that bridges atomic size with the precision of modern measurement tools.