The Physics Of Physics And Physics Essay

1197 Words May 4th, 2015 null Page
The reason people can see through windows and not concrete is because glass is transparent to visible light while concrete is not transparent to visible light. Today, physics can explain how transparency works and allows people to apply the physics to everyday applications that make life better. Light reacts differently with different materials. Three things can occur when light encounters a medium. First, the light ray can be absorbed by the material. According to William Harris, absorption occurs “…when the photon gives up its energy to an electron located in the material…with this extra energy, the electron is able to move to a higher energy level, while the photon disappears” (n.d.). Second, the light ray can be reflected which occurs when the material re-emits a photon of identical energy to the one that was absorbed (Harris). Third, the light ray can transmit through the material making it transparent (Harris). The third phenomenon is the focus of this paper. As previously mentioned, when a photon has enough energy to promote a valence electron to a higher energy state, the photon is absorbed by the material. The amount of energy required to promote the electron is equal to the energy difference of the two energy states. This difference in energy is called the band-gap. Smallman and Bishop state that “if the photons have insufficient energy to excite electrons in the material to a higher energy level, they may be transmitted rather than absorbed and the material is…

Related Documents