A fireball spell generates a searing explosion of flame that detonates with a low roar and deals 1 level of fire damage per caster level to every creature within the area. Unattended objects also take this damage. The explosion creates almost no pressure.
Casting Time 1 Standard Action
Components Material, Verbal and Somatic
A fireball spell generates a searing explosion of flame that detonates with a low roar and deals fire damage to every creature within the area. Unattended objects also take this damage.
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.
Pathfinder SRD Fireball spell- http://www.d20pfsrd.com/magic/all-spells/f/fireball/