system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How do "smart bombs" work? Specifically, how are they guided to the target if they are simply dropped from a plane.
gpt
There are a number of different guidance systems for "smart bombs" but one of the most common uses lasers.

Basically the bomb is released from the plane, and it has sensors in it that constantly scan the ground looking for a laser marker at a specific frequency. So after releasing the weapon, either the bomber aircraft itself, or a support aircraft, will shine a laser at the target.  The weapon then "sees" this laser and attempts to guide itself to where the laser is shining.

Strictly speaking, most laser-guided ordnance are missiles rather than bombs, as they usually have the ability to use propulsion systems to change their course.

Laser-guided missiles are extremely accurate when tested under ideal conditions, but in practice their use is often curtailed due to smoke, low cloud, or even the difficulty of keeping the laser permanently shining at the target during the weapon's flight.