A 
fireball spell is an explosion of flame that detonates with a low roar and deals 1d6 points of fire 
damage per 
caster level (maximum 10d6) to every creature within the 
area. Unattended objects also take this 
damage. The explosion creates almost no pressure.
You point your finger and determine the 
range (distance and height) at which the 
fireball is to burst. A glowing, pea-sized bead streaks from the pointing digit and, unless it impacts upon a material body or solid barrier prior to attaining the prescribed 
range, blossoms into the 
fireball at that point. (An early impact results in an early detonation.) If you attempt to send the bead through a narrow passage, such as through an arrow slit, you must "hit" the opening with a ranged touch attack, or else the bead strikes the barrier and detonates prematurely.
The 
fireball sets fire to combustibles and damages objects in the 
area. It can melt metals with low melting points, such as lead, gold, copper, silver, and bronze. If the 
damage caused to an interposing barrier shatters or breaks through it, the 
fireball may continue beyond the barrier if the 
area permits; otherwise it stops at the barrier just as any other spell effect does.