Convert Femtometer (fm) to Rod (US Survey) (rd (US)) instantly.
About these units
Femtometer (fm)
A femtometer, equal to 10⁻¹⁵ meters, is the scale at which the structure of atomic nuclei becomes measurable. Also known historically as a "fermi," this unit is used extensively in nuclear physics to describe the radii of protons, neutrons, and nuclei, which typically span 1–10 femtometers. At this scale, the strong nuclear force dominates interactions, and classical intuition breaks down almost entirely—quantum mechanics provides the only meaningful framework. The femtometer also plays a role in high-energy particle experiments, where the wavelengths of probing particles (like high-velocity electrons) may be expressed in femtometer increments. These small wavelengths allow researchers to resolve sub-nuclear structures. While invisible to any optical instrument, distances in the femtometer range can be inferred through scattering experiments, such as those performed in particle accelerators.
Rod (US Survey) (rd (US))
The US Survey Rod equals 16.5 US Survey Feet (~5.0292 meters). Like the chain and furlong, it serves as a subdivision of larger units, maintaining consistency with historic Gunter-based measurements. Surveyors historically used rods to measure short distances, delineate boundaries, and calculate acreages. Its simple relationship to chains and furlongs made it practical for field measurements without complex arithmetic. Today, the US survey rod primarily appears in historical records, legal surveys, and when referencing pre-metric property data, providing continuity between older and modern surveying conventions.