hammer

thumb|right|upright=1.3|A modern claw hammer suited to drive and remove nails thumb|Cartwheel mallets with heads of felt held between steel washers for use with [[timpani drums]] thumb|Detail of the head of a war hammer thumb|right|A geologist's hammer used to break up rocks, as seen in [[archaeology and prospecting]]

A hammer is a tool, most often a hand tool, consisting of a weighted "head" fixed to a long handle that is swung to deliver an impact to a small area of an object. This can be, for example, to drive nails into wood, to shape metal (as with a forge), or to crush rock. Hammers are used for a wide range of driving, shaping, breaking and non-destructive striking applications. Traditional disciplines include carpentry, blacksmithing, warfare, and percussive musicianship (as with a gong).