system
Given the following post, respond as if you're commenting on Reddit:
human
Where do the light waves go when you turn of the lights?

This might sound like a joke, but I genuinely don't know the answer.

So, when you turn on the lights, the circuit closes and the lights turn on. The light bulb or whatever sends out beams of light, which are reflected and absorbed by objects. That's my understanding of it, though I might be wrong.

But what happens when you turn off the lights? I get the part that the circuit is interrupted and therefore the light bulb isn't sending out light anymore. But what about those light beams that are already bouncing around the room? Do they just disappear after a while? 

On a similar note, I've been taught that shade is where the light doesn't get to, since light isn't like sound in that the beams are straight and don't go in all directions. But you can still see something in the shadow, it's not just black. Everythings darker, but not completely black.

I'm looking forward to some answers on this, because I really don't get it. Thanks in advance.
gpt
You already answered your own question:

> absorbed by objects

Light that is emitted is very rapidly absorbed by the objects and surfaces it hits. Even light that is reflected once or multiple times ends up being absorbed. This process is extremely fast because of how fast light moves. It takes a mere 3 nanoseconds for light to travel 1 meter. So even bouncing back and forth between two mirrors (which never reflect 100% of the light and always absorb some of it), a beam of light will diminish to a level where it's no longer visible in microseconds or less.

When light is absorbed by an object, that object gains a bit of energy and will therefore heat up ever so slightly.

> On a similar note, I've been taught that shade is where the light doesn't get to, since light isn't like sound in that the beams are straight and don't go in all directions. But you can still see something in the shadow, it's not just black. Everythings darker, but not completely black.

Details in shadows are visible because they're illuminated indirectly or by another light source. Consider an object in a room near a lamp. The lamp casts a shadow behind the object, but details are still visible in this shadow: It's not pitch black. This might be because the area is still illuminated by another lamp elsewhere in the room or it is illuminated by light from the nearby lamp being reflected by the walls or ceiling and taking an indirect path from lamp to the shadow area.