A chick hatching from an egg. The chicken or the egg causality dilemma is commonly stated as which came first: the chicken or the egg?. The dilemma stems from the observation that all chickens hatch from eggs and all chicken eggs are laid by chickens.
Unpolarized light can also become polarized when it is scattered in air (also known as Rayleigh scattering). This occurs due to the fact that the EM waves cause the electron in air to vibrate, producing radiation and causing polarization of the light.
the most striking example of fluorescence occurs when the absorbed radiation is in the ultraviolet region of the spectrum and thus invisible to the human eye while the emitted light is in the visible region which gives the fluorescent substance a distinct color that can only be seen when exposed to uv light