The angstrom equals 10⁻¹⁰ meters or 0.1 nanometers. It is used in chemistry and crystallography for atomic and molecular dimensions. The Bohr radius — the characteristic size of a hydrogen atom — is 0.529 Å. Covalent bond lengths are typically 1–2 Å.
Real-world: A water molecule is about 1 Å across. The covalent bond in H₂ is 0.74 Å. X-ray wavelengths are 0.1–100 Å.
Read full angstrom reference →The furlong equals 201.168 meters or 1/8 of a statute mile. It originated as the length of a medieval English plough furrow — "furrow long". Today it survives mainly in horse racing in the UK, Ireland and North America, where race distances are typically 5 to 12 furlongs.
Real-world: The Epsom Derby is run over 1 mile and 4 furlongs (about 2.4 km). The Kentucky Derby is 10 furlongs.
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