Chimes produce sound because they all have a natural frequency. The natural frequency can be affected by the shape, length, and density of the chime. Since all materials have different shapes and densities they all sound either extremely different or just slightly different. We learned that harder materials such as metal and hard wood resonate better than softer materials like rubber and plastic. Our group chose to use EMT Metal Pipes because they are easy to manipulate to the sizes we wanted, they are cheap, and they resonate nicely. To start our chimes we needed to find our starting pipe. We chose a relatively long pipe because it would make a deeper sound and we needed to make smaller pipes to create an eight note octave. Smaller pipes make a higher pitched noise because they are easier to move. Since they are easier to move they can vibrate faster creating a higher pitch, a shorter wavelength, and a faster frequency. We grabbed a couple of long pipes and hit them to see what ones made a solid note. We found one that was a C and used that one. We then cut pipes slightly shorter and tested them until we hit the next note. We repeated this until we got 8 notes (in inches 14.5 is C, 14 D, 12.5 E , 11.5 F, 10.5 G , 9.6 A, 9 B, and 8.5 C). Once we made all the pipes we made our stand. We attached three pieces of wood together making a upside down U shape. We then drilled holes into the top piece to feed fishing line through to hang our pipes. We had to hang the pipes on the fishing line because it allows to pipe to resonate without stopping it. NoteLength (cm) C36.8 cm D35.5 cm E31.75 cm F29.2 cm G26.7 cm A24.4 cm B22.8 cm C21.6 cm
The reason why a guitar makes noise you can hear is because the string vibrated creates longitudinal waves. We had a 1.05m long piece of wood and drilled bolts into it. We tied the strings around the bolts and the other side of the string we put through a 3in by 1 1/3in piece of wood. The string length is .82 meters. Then we put the wood with strings into a 5 gallon jug and screwed the wood into the jug. We then used a tuning app to find out which notes our guitar played. Our highest (left) string plays a E, our middle string played a G, and our lowest (right) string played an B. When plucked, the guitar string vibrates. This sets the air molecules around the string to compress and rarify the same frequency as the string. The tighter the string, the faster it vibrates, which creates a higher pitch. As a string gets thicker, a lower pitch is produced. A thicker string makes a deeper noise because it vibrates slower than a thinner string. Since it vibrates slower it produces a lower frequency. The sound is projected louder because of the water jug acting as an soundbox. The soundbox amplifies the vibrations of the strings. Soundboxs can range from any shapes and sizes, from a circular hole on an acoustic guitar to 2 f-shaped holes on a violin. Most soundbox are on the front of the sound board, although they can be on the back or the sides, nowhere near the strings. It works the same either way. Half of our strings are actually inside of our sound hole, or the hole we cut out of a 5 gallon jug. A sound box amplifies the noise because the sides of the soundbox can reflect the sound, which is hitting all sides from a lot from angles. Due to the shape of the soundbox, the reflected waves will amplify each other, and focussing the sound outwards in a single direction. To make our string create seven different notes we had to use a graph with the wavelengths and the frequencies (http://www.phy.mtu.edu/~suits/notefreqs.html). To find the distance we needed to hold our finger from the end of our string we needed to take the wavelength and divide it by two. This works because when you pluck the string it creates either a trough or crest. To create a whole wavelength you need a trough and a crest, which would be double the length of the string. NoteLengthWavelength G.82m1.64m A.77m1.54m B.7m1.40m C.655m1.31m D.58m1.16m E.52m1.04m F.49m.98m
The last type of instrument we made was a wind instrument. A wind instrument creates noise because it produces vibrations. We first had do research on how wind instruments work. We learned that each material has a different natural frequency. Natural frequency is the frequency at which a system oscillates when not subjected to continuous or repeated external force. The natural frequency can be effected by the thickness and and the shape of our bottles. Sound is created from blowing into the bottles, because when you blow across the top of the bottle it created different pressure zones. When the bottle has a high pressure zone it pushes the air out the top. It displaces more air than what was originally in the bottle. Evidently sucking more air back into the bottle. The sound we hear is the air getting pushed out when high pressure is created. To create a higher pitch or a faster frequency you have to add more water/liquid into the bottle.This creates a higher frequency because there is less air making the wavelength shorter. If you blow directly into the bottle no sound will be created because the air in the neck of the bottle will act as a shield blocking the air from entering. That is why you have to blow at an angle to create the sound. We found the bottle we wanted to use and found out that its natural frequency is a C. We then filled other bottles of the same size up with different amounts of water until we got all the other notes; C D E F G A B. NoteDistance of Water Level from Bottom. C0 meters D0.04 meters E0.075 meters F0.095 meters G0.12 meters A0.14 meters B0.17 meters
Reflection: I really enjoyed this build a band project. It was fun to create instruments in a different creative way with our group members. What went well is that our group communicated well with each other to build and research the instruments. When some of our group members were getting off task we helped them stay focused right away. When we needed materials to make parts of the instrument we contacted each other what we needed and who would bring it. The second thing that went well was that everyone in the group contributed a lot to the project we were constantly building and testing our instruments to make sure they had the right notes. What went poorly was that we had people absent from school in our group so that made it harder to finish on time and work all together as a team. The second thing that went poorly was that we couldn't find the right tools in order to make some of the instruments. That made it take longer to build. I will continue to work on being a strong team player and leader. I will focus 100% of the time in order to make myself and my group better.