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Physics project: The piano

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joel espinoza

on 8 March 2013

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Transcript of Physics project: The piano

The Physics of Piano Playing The Piano A piano is composed of 88 keys. 36 black keys and 52 white keys.
The average piano has 230 steel-wire strings that are folded underneath these keys.
The length, tension, and diameter of the strings determine their sound. When the keys are pressed down, the strings of the piano vibrate.
The keys of a piano are attached to levers and pivots that release hammers that strike strings when a key is pressed. This way, the hammer is immediately released so that the string can vibrate freely to produce sound.
When a key is pressed down, the wippen is raised. A wippen is the part of the piano that comes in contact with the key and is responsible for transmitting the motion of the key to the hammer to the string. At the same time, the key will raise the damper and the hammer drops. This creates a sound. The damper will then soon fall on the string and stop the sound. Newton's first law: Objects at rest will remain at rest and objects in motion will remain in motion unless acted upon by a force.
This is true with the strings of a piano. They are fixed at two ends and remain at rest unless acted upon by a force.
The fixed strings create standing waves upon being struck and produce sound.
Sound is produced by vibrations in the space around.
The vibrations in the air we hear when listening to music are called longitudinal waves. Structure of a piano How the piano makes sound. Connection to
physics The piano was created around 1720 by Bartolomeo Cristofori of Padua, Italy.
He wanted an instrument with more range of sound than the current harpsichord of the day.
The name piano comes from the Italian word pianoforte which means "loud and soft". This is because you could now control the volume of notes when playing the keys. By: Courtney Hitchcock There are three types of Pianos
1.Grand Piano
2.Baby Grand Piano
3.Upright Piano Sound Sound waves are made of areas of high and low pressure. These are called rarefactions(low pressure) and compressions(high pressure). The wavelength and the speed of the wave determine the pitch or frequency of the sound. Longer wavelengths mean a lower and deeper pitch. The amplitude of a wave determines how loud the sound will be. The greater the amplitude, the louder the sound. The sound wave produced by a piano is a standing wave. A standing wave is the pattern of the total wave amplitude. It consists of nodes and antinodes. The areas of highest vibration are called antinodes and the areas of the lowest vibration are called nodes.
The wave has a fixed node at each end and an antinode in the middle. The waves created by the piano are called transverse waves . To find the resonance of a standing wave, use the equation λn=2L/n. Sound! Frequency! The speed of the wave on a string depends on the tension of the string as well as its mass per unit length. The tighter the string, the faster the wave moves along it.
Therefore it has a higher frequency of its standing waves. Frequency is the number of oscillations in pressure each second.
The faster the wave speed, the higher the frequency and the higher the pitch of the sound of the note. Frequency and notes! A frequency is known as a note in music.
Pythagoras, the Greek mathematician, explained the frequency ratio between notes that are an octave apart. This ratio is 2:1. For example, if a note is pitched at 262 Hz, a note that was an octave higher is at 524 Hz, and a note that was an octave lower is pitched at 131 Hz.
This theorem also applies to the length of the string. If the string of the piano that produces the frequency of 262 Hz is cut in half, the new note will be an octave higher as it has more tension. When two sounds have a ratio of 2:1, this is the same note, just in different pitches. A perfect fifth on the piano, or the first note of a scale and the fifth note of a scale, has a ratio of 3:2 or 2:3. Summary: Frequency, wavelength, amplitude, and shape of the sound waves determine the pitch, volume, and style of the notes being produced by the piano.
The tuning and care of an instrument such as the piano are also determined by physics such as the frequency, and speed of sound are affected by temperature and tension or tightness of the piano strings.
While it may seem like a simple instrument to play or just make noise with, the piano is actually a highly scientific and thought out display of the physics of sound. The End! KEYS Transfer of momentum from fingers to move keys.
Keys are weighted for equilibrium. Hammer Mechanism Torque induces the rotation of the hammer lever arm around a pivot point Strings Pianos need to be tuned by altering tension force Sound Waves The sound wave produced by a piano is a standing wave. A standing wave is the pattern of the total wave amplitude.

Sound box on piano amplifies sound to the ear

Longitudinal waves travel through medium

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