3 words in this vocabulary list
noun A noun is a word that represents a person, place, thing, or idea. In this case, 'atom smashing' is a noun because it represents a process or action of breaking apart atoms.
noun a stream of high-energy electrons or positrons emitted by a radioactive substance or generated by a particle accelerator
noun a type of electromagnetic radiation of very high frequency and energy, emitted by the nuclei of some radioactive substances