Conversion Center

Barleycorn is an old English unit of distance equal to 1/3 inch or about 8.47 millimeters. In farming societies was very common to use seeds as units of length. Barley was a basic crop in England. So barleycorn was a useful unit.

Bohr or bohr radius (a₀) is used in particle physics. One bohr is the mean distance between the proton and the electron in an unexcited hydrogen atom. This unit was named to honor the Danish physicist Niels Bohr (1885-1962), who explained the structure of atoms.