Femtometer
A femtometer (fm) is a unit of length in the metric system, equal to one-quadrillionth of a meter (1 fm = 10⁻¹⁵ meters). It is also known as a fermi, named after the physicist Enrico Fermi. Femtometers are used to measure extremely small distances at the subatomic level, such as the size of protons, neutrons, and atomic nuclei. For example, the radius of a proton is about 0.84 femtometers. This unit is commonly used in nuclear physics and particle physics, but it's far too small for everyday measurements.
Rod (US Survey)
The US survey rod is a unit of length used in U.S. land surveying. It is defined as exactly 16.5 US survey feet, which is slightly longer than the international foot. Since one US survey foot equals approximately 0.3048006096 meters, the US survey rod measures about 5.0292 meters.
The survey rod, also called a pole or perch, is historically significant in the U.S. Public Land Survey System and is used to measure land boundaries and distances.
Key facts:
1 US survey rod = 16.5 US survey feet
1 US survey rod ≈ 5.0292 meters
4 US survey rods = 1 US survey chain
40 US survey rods = 1 US survey furlong
Though the US survey foot and related units are being phased out in favor of international units, the US survey rod still appears in legal land descriptions and older surveying documents.
No conversions available for length.