Pianos are typically made of wood, cast iron, steel and felt, among other materials. Wood alone constitutes more than 85 percent of the instrument. Player pianos and digital pianos also include mechanical and digital components.
The piano evolved from the harpsichord in the 1700s when Bartolomeo Cristofori developed a new type of hammer action; this allowed musicians to play both loudly and softly. The word piano comes from the Italian "pianoforte" (soft loud). Initially, musicians such as Bach objected to the new instrument, but they were eventually won over.
Early pianos were built one at a time by craftsmen. The Industrial Revolution in the 1800s sped up the process and made pianos accessible to common people. Once pianos were more readily available in the early 20th century, manufacturers encouraged music lessons for school children, increasing demand.
The piano is comprised of three major components. The wooden case forms the body of the instrument. The strung back contains the cast-iron frame, strings and soundboard. The playing mechanism includes the levers and hammers that hit the strings.
Different types of wood are used in pianos, each chosen for its distinct properties. For example, sugar pine is chosen for soundboard ribs because of its strength and flexibility. Yellow birch is used in keybed caps and legs because of its hardness and shape retention. One piano may contain several types of wood.