Gray (unit) Gray (unit) The gray (symbol: Gy) is a derived unit of ionizing radiation dose in the International System of Units (SI). It is defined as the absorption of one joule of radiation energy per kilogram of matter. It is used as a unit of the radiation quantity absorbed dose which measures the energy deposited in a unit mass at a certain position, and of the radiation quantity kerma, which is the amount of energy that is transferred from photons to electrons per unit mass at a certain position. The corresponding cgs unit to the gray is the rad (equivalent to
The Logic of Scientific Discovery The Logic of Scientific Discovery The Logic of Scientific Discovery is a 1959 book about the philosophy of science by Karl Popper. Popper rewrote his book in English from the 1934 German original, titled "Logik der Forschung. Zur Erkenntnistheorie der modernen Naturwissenschaft", which literally translates as, "Logic of Research: On the Epistemology of Modern Natural Science"'. Popper argues that science should adopt a methodology based on falsifiability, because no number of experiments can ever prove a theory, but a reproducible experiment or observation can refute one. According to Popper: "non-reproducible single occurrences are of no significance to science. Thus a