[https://www.youtube.com/watch?v=a0H0vOWUjbY](https://www.youtube.com/watch?v=a0H0vOWUjbY)
Was recently watching the new Allen Pan video on making a laser grid lawn mower, and I was just confused by why we can see the lasers on the video, when it seems him and his friends couldn’t. At 6:45 it seems clear that Backyard Scientist uses his camera to see the lasers themselves because they wouldn’t be visible unless they shined the light into their eyes, but the camera can pick up the path of the lasers?
In: Physics
You can only see the paths of a beam of light because the beam is reflecting off particles in the air or being scattered by the medium itself. Unless you were really, really careful about the space you were in, you’re always going to get some of that scattering. Cameras can pick up even the very faint scattering with a long enough exposure because they’re effectively integrating the light hitting the sensors over time, but human eyes are more dynamic and relative and don’t pick up really faint light easily while adjusted for brighter light (such as looking at where the beam is reflecting off something)
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