Convert Bohr Radius (a₀) to Long Reed (long reed) instantly.
About these units
Bohr Radius (a₀)
The Bohr radius, equal to approximately 5.29177 × 10⁻¹¹ meters, is the most probable distance between the electron and nucleus in the ground state of hydrogen according to the Bohr model. While modern quantum mechanics has evolved far beyond the Bohr model, the radius remains a remarkably accurate approximation for average atomic dimensions. The Bohr radius acts as a natural "yardstick" for the size of atoms and is frequently used in atomic physics and quantum chemistry. Many atomic properties — orbital sizes, electron probability distributions, and energy levels — are conveniently expressed in multiples of the Bohr radius. Because it reflects fundamental constants, including Planck's constant and the electron charge, the Bohr radius also appears in theoretical analyses of physical systems and helps unify atomic physics concepts across different contexts.
Long Reed (long reed)
The long reed is a traditional unit of length used in Egypt and other ancient cultures, roughly equivalent to 2 cubits. It was employed in surveying, architecture, and the measurement of agricultural fields. The unit's length made it suitable for laying out longer distances with relatively few measurements, especially in river valley contexts where precision at large scales was important for irrigation and crop management. Historical records show the long reed in use for temple construction, pyramidal measurements, and land division, illustrating the practical integration of human-based units into early engineering practices.