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
Orders of magnitude (mass) Orders of magnitude (mass) To help compare different orders of magnitude, the following lists describe various mass levels between 10 kg and 10 kg. The table below is based on the kilogram (kg), the base unit of mass in the International System of Units (SI). The kilogram is the only standard unit to include an SI prefix ("kilo-") as part of its name. The "gram" (10 kg) is an SI derived unit of mass. However, the "names" of all SI mass units are based on "gram", rather than on "kilogram"; thus 10 kg is a "megagram" (10 g), not a