Eli5 Why light waves require line of sight while sound waves do not?


Eli5 Why light waves require line of sight while sound waves do not?

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They don’t really. Think of someone in the next room turning on a light and you’re around a corner. Those light waves are reflecting off of walls and other surfaces and you see them. If you look outside your window during the day, you see what is outside. That is reflected sunlight. You don’t need direct line of sight because light will reflect off of objects. That is literally how you see.

Sound does the same thing. You’ll hear it best directly from the source, but you’ll still hear it as sound waves bounce off of the environment.

The clue is in the question: line of *sight*. That’s literally the definition of what’s required for visible light to travel.

Because they are something completely different.

Light is electromagnetic radiation… (Visible light is only small part of the spectrum)

Sound is vibration. This means it can vibrate other things. It can travel through solid matter and back to air.

Both light and sound can bounce or reflect. Think about being in a room where you can’t see a window and there is no light on, but it’s light outside. You can still see in the room, right? That’s because the light from the window is bounding off of the walls. Sound does the same thing.

You can be in an environment where neither light nor sound will bounce. In an anechoic chamber (a specialized room / chamber that is designed to prevent reflections of sound), you would need direct line of sight (sound?) to hear a sound. If the chamber was also perfectly black in color (or otherwise did not reflect light), you would also need line of sight to see light.