Freedom's Sound - Izzit.org

Freedom’s SoundScienceParts of a pianoaction:bridge:The action may be made up of hundreds of parts! The way the keys lift the hammers sothey can strike the strings is called the action of the piano.Strings pass over two bridges. The distance between the bridges is called a string’s“speaking length,” which is the part of the string that vibrates when struck by thehammer. The bridge is also used to send the energy of the vibrating string to thesoundboard for amplification.damper: These are wood and felt pieces (they were red in Freedom’s Sound) that stop unwantedvibrations. When you press a key, the damper moves away (raises) so that the stringcan vibrate. When you stop pressing the key, the damper falls back onto the string tostop the vibration.frame:This is made of cast iron and keeps tension on the strings.hammer: This is a small, felt-covered wooden club. When the hammer hits the string, the stringbegins to vibrate.key:lid:pedals:pins:This is a wooden lever that acts like a seesaw. Pressing a key makes the hammer hitthe string and makes it vibrate.This is the top of the cabinet. It can be opened to increase the amplitude of the sound.These are metal levers that you press with your feet. They can increase or decreasethe vibrations, depending on which lever you choose.These hold the strings in place. They can be tightened or loosened to adjust the tone.This is what the piano tuner works with.sound board: This is the part of the piano that takes vibrations from the strings andamplifies them so they are louder.strings:These vibrate and make sound waves. Thicker strings have lower tones because thethickness slows down the vibrations. Shorter strings vibrate less and have smalleramplitude.www.izzit.org

Freedom’s SoundScience (continued)The parts of a piano can be separated into three categories according to how they help a pianomake sound. Classify the parts listed above into these three categories.Sound makersParts that make the soundAmplifiersParts that increase volume ofthe strings by amplifying theenergy of the vibrating stringsMechanicsParts that convert the action ofthe piano player into stringvibrations1. One change made by the Estonia Piano Company was to buy wood for sound boards fromAustria and Switzerland. In these areas, the trees are slow growing and the tree rings arenarrower. What factor(s) would cause the rings to be more narrow?2. It is necessary to tune pianos because metals expand and contract with temperaturechanges. What common household item uses this phenomenon to make our lives easier?How does this make life challenging?3. The vibrations of a piano’s strings are too quiet to be heard. Using a sound board allowsfor sound to be amplified by allowing the string vibrations to be spread throughout thesound board. We also use sound boards in music boxes. Can you think of any other areawhere sound boards are used? Where might you use a sound board?www.izzit.org

Freedom’s SoundScience – Answer GuideSound makersParts that make the soundstringspinsAmplifiersParts that increase volume ofthe strings by amplifying theenergy of the vibrating stringssoundboardpedalcabinetlidbridgeMechanicsParts that convert the action ofthe piano player into stringvibrationsdamperframekeyhammeraction1. One change made by the Estonia Piano Company was to buy wood for sound boards fromAustria and Switzerland. In these areas, the trees are slow growing and the tree rings arenarrower. What factor(s) would cause the rings to be more narrow?Colder climates produce a shorter growing season and thus narrow rings.2. It is necessary to tune pianos because metals expand and contract with temperaturechanges. What common household item uses this phenomenon to make our lives easier?Many household thermostats use bimetallic strips (2 metals that have different rates ofexpansion) to tell the furnace and air conditioner when to turn on and off. How does thismake life challenging? The expansion and contraction of materials can cause manyproblems, for example pavement often buckles in hot summer weather. You may finddoors in your house easier or harder to close during different seasons. Also, engineersmust take this expansion/contraction into account when building bridges and otherstructures.3. The vibrations of a piano’s strings are too quiet to be heard. Using a sound board allowsfor sound to be amplified by allowing the string vibrations to be spread throughout thesound board. We also use sound boards in music boxes. Can you think of otherinstruments where sound boards are used? Guitars, violins and other string instruments.In banjos the sound board can be skin or other materials. Where might you use a soundboard? Student answers will vary. Teachers should encourage creativity and divergentthinking.www.izzit.org