Why can't you see around corners?
You can hear around corners because sound spreads in all directions, but you cannot see around them because light nearly always travels in straight lines. One way of getting around this is to use a mirror. This reflects the light around the corner, so you can see what, or who, is hiding behind it.

Light you cannot see
If the beam of light shone past your nose in completely empty outer space, you would not be able to see it. The reason for this is that you can see light only when it shines into your eyes. On Earth, you can see beams from the side because dust and air scatter some of the light your way.