if you point a laser beam to a mirror in a dark room how come you cant see it's path to the mirror?

Question

using one of those red light laser pointers

Answer 1

To be able to see the laser beam of light, there would have to be a significant amount of particles in the air for the light to "bounce" off of.

Answer 2

Coherent light scatters less. If there's nothing to scatter off (dust, moisture particles), the beam will not be visible - Hollywood special effects notwithstanding.

Answer 3

You also can't see the "Beam" of a flashlight as it travels to the surface it strikes, unless there is also dust or fog or smoke in the air.

You don't see light unless it has been scattered.