Help me understand grade lasers?

Question

Having hard time understanding grade lasers, so if one spot needs to be say 4'5 and you shoot grade there and the other spot needs to be 5'5 how does the laser know ??

Answer 1

The laser is just a dead straight line of light. The rod you place at different places for a reading has a reflector on it and when the laser hits the rod the rod reads out the distance to zero mark that was set up when you set up the laser level in the first place. Just think of shooting at a target with a rifle. You hit the target and then don't raise or lower the rifle. your buddy moves the target to a lower part of the landscape and the rifle that has not moved is shot again. this time you hit the target but the bullet hits 8 inches higher than last time. So the place the target is sitting is 8 inches lower than were the target was for the first shot. The laser never moves up or down its just straight. The rod, target gets hit in different spots and the space between the different spots is the up and down of the land. Get it now?? I hope so.