Nonspecific fever. Kids infected with coxsackievirus usually establish an unexpected fever that lasts about 3 days. Often the fever comes in two waves â it is there for a day or two, disappears for a couple of days, then returns for about 3 days.
Albert Einstein proposed the idea the light exists of quanta of energy that he called photons.
It is one of the strange, but fundamental, concepts in modern physics that light has both a wave and particle state (but not at the same time), called wave-particle dualism. Perhaps the foremost scientists of the 20th century was Niels Bohr, the first to apply Planck's quantum idea to problems in atomic physics.