Environmental radioactivity g) to that of the soil water (Bq ml). If the radioactivity is tightly bonded to by the minerals in the soil then less radioactivity can be absorbed by crops and grass growing in the soil. One dramatic source of man-made radioactivity is a nuclear weapons test. The glassy trinitite formed by the first atom bomb contains radioisotopes formed by neutron activation and nuclear fission. In addition some natural radioisotopes are present. A recent paper reports the levels of long-lived radioisotopes in the trinitite. The trinitite was formed from feldspar and quartz which were melted by the heat. Two samples
Mole (unit) 1%. The name "mole" is an 1897 translation of the German unit "Mol", coined by the chemist Wilhelm Ostwald in 1894 from the German word "Molekül" (molecule). However, the related concept of equivalent mass had been in use at least a century earlier. The mole was made the seventh SI base unit in 1971 by the 14th CGPM. At the 26th CGPM the definition of the mole was changed from a number derived from a weight (the number of atoms in 12 grams of carbon-12, C) to directly being equal to Avogadro's constant. Since its adoption into the International System