J. Physical and Chemical Sciences Volume 6 / Issue 3 ISSN: 2348 – 327X 1 JOURNAL OF PHYSICAL AND CHEMICAL SCIENCES Journal homepage: http://scienceq.org/Journals/JPCS.php Review Open Access A Theoretical Verification of Invalidity of the Law of Conservation of Mass: The Cases of Nuclear Species and Nuclear Processes Belachew Desalegn 1* , Getahun Getachew 2 1,2 Department of Physics, Wolaita Sodo University, PO box 138, Wolaita Sodo, Ethiopia * Corresponding Author: Belachew Desalegn; Email: belachewdesalegn76@gmail.com Received: March 15, 2018, Accepted: May 05, 2018, Published: May 05, 2018. ABSTRACT The law of conservation of mass which suggests the absoluteness of mass by stating that the mass can never be created nor destroyed nor changed even at nuclear species level and during nuclear processes(nuclear reactions, radioactive decays, etc.), is no longer founded. Of course, within some problem domain, the amount of mass remains constant-mass is neither created nor destroyed. This seems quite obvious, as long as we are not talking about nuclear species or very exotic physics problems and processes. When we move a solid object the object retains its shape, density, and volume. On the other hand, in another domain, the result of the law of conservation of mass is quite not the same. It is found that the rest mass of nuclear species is measurably smaller than the sum of the rest masses of its constituent protons and neutrons. Mass is no longer considered unchangeable in this domain. Besides, the law of conservation of mass is proved to be invalid in basic nuclear processes like nuclear decays and nuclear reactions. Therefore, the aim of this article is to discuss some problem domain where the law of conservation of mass is not valid and along the way to reveal that the absoluteness of mass is recently not acceptable. Keywords: Mass, Law of conservation of mass, Nuclear species, Nuclear processes INTRODUCTION At the beginning of the 20th century, the notion of mass underwent a radical revision. Mass lost its absoluteness. One of the striking results of Einstein’s theory of relativity is that mass and energy are equivalent and convertible one into the other. Equivalence of the mass and energy is described by Einstein’s famous formula E = mc 2 . In words, energy equals mass multiplied by the speed of light squared. Because the speed of light is a very large number, the formula implies that any small amount of matter contains a very large amount of energy. The mass of an object was seen to be equivalent to energy, to be interconvertible with energy, and to increase significantly at exceedingly high speeds near that of light. The total energy of an object was understood to comprise its rest mass as well as its increase of mass caused by increase in kinetic energy [1,2,3]. In special theory of relativity certain types of matter may be created or destroyed, but in all of these processes, the mass and energy associated with such matter remains unchanged in quantity. It was found the rest mass of an atomic nucleus is measurably smaller than the sum of the rest masses of its constituent protons and neutrons. Mass was no longer considered unchangeable in the closed system. The difference is a measure of the nuclear binding energy which holds the nucleus together. Furthermore, the nuclear binding energy is the energy required to break up the nucleus into its separate nucleons or this can be expressed as the energy released when the nucleus is formed from separate nucleons and is equal to the decrease in potential nuclear energy of the nucleons when they come together. According to the Einstein relationship (E = mc 2 ) this binding energy is proportional to this mass difference and it is known as the mass defect [4,5]. In general, the conservation of mass is a fundamental concept of physics along with the conservation of energy and the conservation of momentum. Within some problem domain, the amount of mass remains constant-mass is neither created nor destroyed. This seems quite obvious, as long as we are not talking about nuclear species or very exotic physics problems including nuclear decays and nuclear reactions. The mass of any object can be determined by multiplying the volume of the object by the density of the object. When we move a solid object the object retains its shape, density, and volume. The mass of the object, therefore, remains a constant between two states. For the obvious reason, mass may be absolute for this kind of matter [6,7]. On the other hand, nuclear species(nuclides), which are made up of protons and neutrons, have unique nature and characteristics. Moreover, nuclides are made up of neutrons and protons, but the mass of a nuclide is not the same as the sum of the mass of the neutrons and protons of which it consists. The mass of a nuclide is less than the sum of the masses of the protons and neutrons of which it is made up. The difference in the masses is referred to as the mass defect. In other words, the principle of conservation of mass, which states that ''mass can never be changed'', is not valid for nuclear species and any nuclear processes. Hence, the law of conservation of mass which suggests the absoluteness of mass by stating that the mass can never be created nor destroyed nor changed at all even at a level of nuclear species and during any nuclear processes (nuclear reactions and nuclear decays), is unfounded. To this end, it is possible to conclude that mass is not always conserved but it can only be approximately conserved [1,2]. Accordingly, the objective of this article is to reveal that the law of conservation of mass which suggests the absoluteness of mass is no longer true. In the following sections, we will further summarize the historical developments of the concept of conservation of mass, and we will discuss the relationship between binding energy and mass defect. Historical developments of the concept of conservation of mass The concept of conservation of mass has gone through different historical developments. It is summarized as follows: Ancient Times The ancient Greeks proposed the idea that the total amount of matter in the universe is constant.