sciencetalk

RensH schreef:Bijvoorbeeld een blauwe kunststof pen, deze is blauw doordat vrije electronen in de kunststof in een andere baan komen door een foton. De energie van de foton wordt dus omgezet. Als de electronen weer terugkeren in de oorspronkelijke baan wordt de energie die weer vrijkomt omgezet in een andere foton. De frequentie van het licht (de kleur dus) wordt bepaald door de baan waarin de electron zich bevindt en/of wat voor soort stof het is.

De overige fotonen (welke de kernen raken?) worden omgezet in warmte.

Tot dusver, klopt dit een beetje?

Antoon schreef:hebben alle voorwerpen die we kunnen zien vrije electronen?(volgens mij alleen metaal atomen en koolstof)(radicalen)

en bevat inkt vrije electronen? dat kan best maar is nieuw voor mij.omdat het geen metaal is.

niet alle fotonen die de kern raken worden omgezet in warmte, maar alleen de infrarood straling.(of ook ultraviolet??)

niet alle voorwerpen die we kunnen zien bevaten vrije elektronen. een isolator bevat geen vrije elektronen, en toch kunnen we dit materiaal zien. de aanwezeigheid van vrije elektronen in een materiaal impliceert dat het materiaal geleidend is.

  1. If the photon has insufficient energy to boost the electron to its next higher possible orbit, the electron cannot hold the energy, and releases it again at once, as a photon that matches the incoming photon. The direction of the released photon depends on the nature of the material substance and the energy of the photon itself, so we get phenomena such as reflection and refraction.  

  2. If the photon has exactly the energy needed to boost the electron to the next higher allowable orbit, the photon will disappear as all of its energy is imparted to the electron. This is a quasi-stable situation; either this electron or another orbiting electron will seek to lose energy by dropping into the vacated orbit, and will release a photon of exactly that energy when it does so.  

  3. If the photon has eneough energy to boost the electron beyond the next orbital energy level, and possibly to a yet higher orbit around its nucleus, it will do so, and the electron will emit a lower-energy photon if necessary, as it initially drops to the highest-energy orbit it can reach. In the meantime, however, another orbiting electron will lose energy by dropping into the vacated orbit, and will emit a photon of its own as it does so. We see this phenomenon in fluorescent lights. Here, the actual source of light energy is UV light produced by a mercury vapor arc through the glass tube. This would normally be very damaging to the eyes, were it not for the phosphors coating the inside of the glass. That coating absorbs the UV light and emits visible light in return.  

  4. The photon doesn't always give up all of its energy to the electron it strikes. Under some circumstances, it only gives up part of its energy to the electron, and both a higher-energy electron and a lower-energy photon leave the point of impact. This is known as the Compton Effect. A practical example of this is found in greenhouses, where some wavelengths of incoming sunlight are converted to longer-wavelength infrared (heat) photons, which are then primarily reflected by the glass panes and are therefore trapped inside the greenhouse.  

  5. Some substances absorb the energy of most incident photons and either transmit (eg., a colored filter) or reflect (eg., a painted surface) photons of a specific amount of energy only. The chlorophyll in green plants gets its energy by reflecting only green light, and absorbing the energy of photons of other colors.