To bring our Light series to an end, we thought it’s appropriate to discuss how light is made. Now, while this does apply to both natural and artificial light, the analogies used will focus mainly on artificial light, since man-made things are often a little easier to understand than the sun is.
The two MVPs that are involved in the process of making light are electrons (which are inside an atom) and photons. Think about someone who would stay in bed and just watch TV all day if they could (no judgement, we would too). Electrons are the same way. They like to stay at what is referred to as the “ground state”, which is a spot where they have to energy. While the ground state technically has a negative value, we’re going to pretend it’s value is zero to help with any confusion (and because the value differs between types of atoms).
Remember that person we had you think about? Only a few specific things are going to get that person out of bed, right? One of which, might be an alarm clock. Photons are pretty much the alarm clocks for electrons. Photons will pass through an atom, and if it happens to be in line with the electron, the photon will be absorbed by it. The tricky part to this is that electrons can only absorb a few specific kinds of photons. So if the values aren’t correct, the electron will just sleep trough that specific alarm and wait for the next to go off.
Once a photon with the right value (again, any values assigned are only to aid in understanding, actual values differ from atom to atom) comes through and wakes up that electron, the electron jumps to what is referred to as an “excited state”. The excited states are important in creating light, since an atom will not produce any light if it’s electron is just laying in bed. When you turn on your lamp, energy is shot into the light bulb (which is filled with atoms). This energy makes sure that not only do the electrons wake up, but that they also get out of bed, have breakfast, and head out the door for work.
Just like us, electrons like to get home as soon as they can instead of staying at work. Given the opportunity, the electron will attempt to release that photon. This means that the electron will jump back down to the ground state and be able to go back to bed with no energy left. The energy that was originally absorbed by the electron is now a photon that has been ejected, leaving the electron and becoming a source of light. A photon being emitted doesn’t mean that that electron is useless anymore- the electron will continue to repeat this sleep, eat, work cycle as long as either: 1. you keep the light on, or 2. it doesn’t become ionized (but that’s a different story).
Thank you for joining us for this series explaining different aspects of light. We hope you’ve been able to learn something new from these articles! New topics will be covered soon, so stay tuned.
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*All photos were created for simple visual representations only. Images are not correct beyond this level.