We use light everyday. It is essential to our lifestyle. How is it produced at an atomic level?
To us, light is vital to life. By discovering fire, ancient humans discovered an energy source that gave off both heat and light energy. The light bulb also revolutionized way people lived. As Thomas Edison, the inventor, once said, “We will make electricity so cheap that only the rich will burn candles.” Soon, people all around were using electricity to produce light. But…How is the light produced in the first place?
To fully understand how light is produced, one must understand the patterns of electrons. Electrons circle around atoms in orbits. The orbits are systematic. The first orbit around the nucleus of an atom can only hold two electrons. The second and third orbits can each carry a maximum of eight electrons. Basically, the orbits get bigger as you go further from the nucleus. It makes sense. And yes, that is why the periodic table is arranged in such a way. If you look, the first row of the table has two elements, the second and third have eight, and so on.
When electrons gain energy, or get excited, they can “jump” up an orbit. Then, they quickly lose that energy, and fall back down to the original orbit. When they fall back down, the electrons give off a tiny ray of light, known as a photon. Lots of photons result in the light that we see and use everyday.
Now, there is different colored light, and there is a reason for that. Remember the visible light spectrum? Red, orange, yellow, green, blue, indigo, and violet? Basically, the more energy the photon has, the higher up that list it goes. So the highest level of energy for wave in the visible light spectrum is violet, and the lowest is red. That is why everyday laser pointers are red, because the energy for red is the lowest, and least likely to hurt someone.
So, basically what happens when you turn a light on is that the energy goes up into the bulb and filament. The electrons get exited by the electricity, causing them to “jump” up an orbit, then fall back down, emitting light!
The cave people didn’t know it, Thomas Edison didn’t know it during his invention, but now you know how light is produced!
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