Like I understand light is photons. But from whence the photons? How come if I’m in a dark room (by the way, why is the room dark? Why no photons in the room?) and I turn on a flashlight, suddenly there’s photons everywhere?
In: Physics
Light is indeed photons, but that isn’t the most intuitive explanation for your purposes. Photons are useful when you are talking about quantization of light, or when thinking about light as particles, but it’s better, for your question, to think of light as energy or as waves (yes, light is both a wave and a particle, I know, super weird).
Let’s talk about energy first, because that’s easier to wrap your head around. Light is a type of energy. When you use a device like a torch or a candle, you convert stored energy (chemical energy in the battery or the wax) into light energy. That’s why the dark room has photons of light bouncing around when you turn on the flashlight, and no more light when the battery dies.
Now let’s talk about waves. Think of the entire universe being filled with this substance or field. You can’t touch it, you can’t feel it, it just… exists. Analogous to the atmosphere itself – you don’t have any awareness of it. Until, of course, it is disturbed. If the atmosphere is perturbed and the wind blows against your face, you realise that there is actually some type of medium around you.
Light is very similar. There is a field all around you called the electromagnetic field. When this field is perturbed (think of someone throwing a pebble on to a lake), the ripple that forms and travels out? We have devices that can observe those ripples. Two of them, in fact, and they’re round, squishy, and located in your head (yep, eyeballs). Our eyes have somehow evolved to react to perturbations in this field whenever someone metaphorically tosses a rock into it (which, remember, you can do when you convert energy).
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