A bell (old Saxon: bellan, to bawl or bellow) is a simple sound-making device. The bell is a percussion instrument and an idiophone. Its form is usually a hollow, cup-shaped acoustic resonator, which vibrates upon being struck. The striking implement can be a tongue suspended within the bell, known as a clapper, a separate mallet or hammer, or in small bells a small loose sphere enclosed within the body of the bell.
Bells are usually made of castmetal, but small bells can also be made from ceramic or glass. Bells range in size from tiny dress accessories to church bells 5 meters tall, weighing many tons. Historically, bells were associated with religious rituals, and before mass communication were widely used to call communities together for both religious and secular events. Later bells were made to commemorate important events or people and have been associated with the concepts of peace and freedom. The study of bells is called campanology.
A set of bells, hung in a circle for change ringing, is known as a ring of bells or peal of bells.
A set 23 of bells spanning at least two octaves is a carillon.
Pisa (pron.: /ˈpiːzə/; Italian pronunciation: [ˈpiːza]) is a city in Tuscany, Central Italy, on the right bank of the mouth of the River Arno on the Tyrrhenian Sea. It is the capital city of the Province of Pisa. Although Pisa is known worldwide for its leaning tower (the bell tower of the city's cathedral), the city of over 88,332 residents (around 200,000 with the metropolitan area) contains more than 20 other historic churches, several palaces and various bridges across the River Arno.
The city is also home of the University of Pisa, which has a history going back to the 12th century and also has the mythic Napoleonic Scuola Normale Superiore di Pisa and Sant'Anna School of Advanced Studies as the bestSuperior Graduate Schools in Italy.