The key difference between natural and artificial radioactivity is that the natural radioactivity in the form of radioactivity takes place on its own in nature whereas when it is induced by man in laboratories, it is called artificial radioactivity.
Man did not invent the process of radioactivity; it was there, existing in the universe since time immemorial. But it was a chance discovery by Henry Becquerel in 1896 that the world came to know about it. Furthermore, the scientist Marie Curie explained this concept in 1898 and earned a Nobel Prize for her work. We refer the type of radioactivity taking place in the world (read stars) on its own as natural radioactivity while that which man induces as artificial radioactivity.
What is Natural Radioactivity?
In general, radioactivity refers to the release of particles and energy from unstable nuclei. The release of particles from unstable atoms continues until the substance reaches stability. This decomposition of the nuclei is the process of radioactivity. When this decomposition takes place in nature, we call it as natural radioactivity. Uranium is the heaviest occurring natural element (atomic number 92).
Radioactivity involves the emission of three types of particles by an unstable nucleus in an effort to reach stability. We name them as alpha, beta, and gamma radiations. Alpha particles consist of two protons and two neutrons (exactly like a helium atom) which is why it has a positive charge. Alpha particles are very small fragments of the parent nucleus that tries to release energy and alpha particles in an attempt to become stable.
Beta particles consist of electrons and are therefore have a negative charge. Third and final particles that a radioactive nucleus emits are gamma particles that are consisting of high energy photons. In fact, they are nothing but pure energy without mass. Not all three radiations take place in case of an unstable nucleus at the same time.
What is Artificial Radioactivity?
When we prepare unstable nuclei in labs via bombarding them with slow-moving neutrons, we call it artificial radioactivity. Though there are radioactive isotopes of thorium and Uranium, artificial radioactivity means that we are creating a series of trans-uranium elements that are capable of radioactivity.
This type of radioactivity has many uses in nuclear reactors where slow-moving neutrons are made to bombard a stable isotope of uranium that becomes unstable and starts to decay releasing a huge amount of energy. Consequently, we can use that energy to turn water into steam. Afterwards, this steam will move turbines producing electricity. Artificial radioactivity has another important use in atom bombs where fission of unstable nucleus results in the release of huge amounts of energy and we cannot control the reaction there. However, in nuclear reactors, the reaction is controlled.
What is the Difference Between Natural and Artificial Radioactivity?
Natural radioactivity is the process of radioactivity that takes place naturally whereas artificial radioactivity is the process of radioactivity that is induced by man-made methods. Therefore, the key difference between natural and artificial radioactivity is that natural radioactivity is the form of radioactivity takes place on its own in nature whereas when it is induced by man in laboratories, it is called artificial radioactivity. Furthermore, natural radioactivity is spontaneous while artificial radioactivity is non-spontaneous. Hence we need to initiate the radioactivity to get the artificial radioactivity.
The below infographic presents more details on the difference between natural and artificial radioactivity
Summary – Natural vs Artificial Radioactivity
Natural and artificial radioactivity are the two major forms of radioactivity. The key difference between natural and artificial radioactivity is that the natural radioactivity is the form of radioactivity takes place on its own in nature while that which man induces is artificial radioactivity.