&gt; <i>a quantum effect that&#x27;s visible in very large systems</i><p>Well, in a certain sense, chemistry and solid state, and the very existence of atoms are also macroscopically-visible quantum phenomena.<p>You do a science class with kids in school and show them static electricity, little pieces of paper dancing in an electric field - that&#x27;s quantum. That&#x27;s electric fields interacting, which is an exchange of virtual photons, which is a quantum phenomenon.<p>We really are jut waves on the surface of an ocean of quantum phenomena.