Red spots made by lasers
Teaching Guidance for 11-14
Why is it safe to look at the red laser spot on the wall and not at the laser directly?
We'd suggest that it pays to emphasise that laser light is reflected from the rough surface of the wall in all directions (diffuse reflection), so that all of the class can see the spot no matter where they are sitting. For each observer only a very small fraction of the original beam passes into their eyes, which means that it is safe.