- Waves And Optics Spring 2022 Project Description Singing Glasses The Project Aims At Studying The Sound Produced By Some 1 (38.03 KiB) Viewed 33 times
- Waves And Optics Spring 2022 Project Description Singing Glasses The Project Aims At Studying The Sound Produced By Some 2 (38.03 KiB) Viewed 33 times
- Waves And Optics Spring 2022 Project Description Singing Glasses The Project Aims At Studying The Sound Produced By Some 3 (33.49 KiB) Viewed 33 times
- Waves And Optics Spring 2022 Project Description Singing Glasses The Project Aims At Studying The Sound Produced By Some 4 (47.89 KiB) Viewed 33 times
- Waves And Optics Spring 2022 Project Description Singing Glasses The Project Aims At Studying The Sound Produced By Some 5 (36.46 KiB) Viewed 33 times
Waves and Optics Spring 2022 Project Description Singing Glasses The project aims at studying the sound produced by some glasses when they are rubbed with wet finger as example of sound produced by standing waves with circular boundary conditions. The study covers an experimental part to find out the change of the frequency of the sound produced with the level of water in the glass. A theoretical part aims to describe qualitatively the phenomena, determine the main parameters responsible of change of frequency, and study the different mode of oscillations or harmonics. Report format Each student should submit hard copy individual report for the project The report should be about 10 pages with figures and tables. Student can add as many appendices as he estimates necessary to develop ideas and clarifications The report should contain the following: • Summary • Introduction • Development of the study in topics with separate title for each one Conclusion List of figures and tables List of References Figures, tables and references should be numbered and referenced in the text. For example (Fig. 1) or (Table 1). For reference you can use carets like [1] instead of (Ref. 1) The reference should mention: The title of the article or book. Author if available • For books: o Book title o Editor
o Pages of the article Year of edition For article in journal or revue The name of the journal o Volume and number o Pages For Internet site Website name o Date of publication URL address Optional topics The treatment of any optional topic related to the subject of the project (proposed in this description or suggested by the student) can leads to eventual bonus in project evaluation up to 10% of total project mark. • Optional topics (if any) should be included in the appendices. Due Time Reports should be submitted before Thursday 05 May 2022 Topics to be treated Introduction • Describe what is singing glass and how to produce sound. • Historical overview of music produced by singing glasses, Experiments Preliminary experiments • Buy a stem glass as shown in the picture. • Fill it partially with water. Hold down the base of the glass with one hand, • Wet a finger of the other hand. • Rub your finger around the rim of the glass while pressing down gently. • Try many times by changing gently the pressure and the speed of your
finger on the glass (pay attention not to press strongly, you may have the risk to break the glass). With the right amount of pressure, the glass will vibrate, sounding a musical note. • Repeat the experiment many times to be familiar with the method of producing sound using glasses Change the quantity of water in the glass and notice the change of the frequency Write your observation Measurement The objective of this part is to make a qualitative study of the change of frequency with the height of water in the glass. • Use an "Audio Spectrum Analyzer" to measure the frequency of resonance. You can download such a software from the internet and install it on your computer, laptop, iPad, mobile, .... or you can use online spectrum analyzer. Choose software giving directly the frequency of maximum intensity • Use a very thin rod with graduation (cach I cm for example) to measure the heighth of water from the bottom of the glass. • Make the following for different heights of water starting from an empty glass and ending at almost fully filled glass (Choose minimum 5 different heights): For each height of water, measure the frequency f of maximum intensity produced by the glass using "Audio Spectrum Analyzer". Take a snapshot of the spectrum showing the frequency of maximum intensity and the frequencies of higher harmonics Repeat the measurement for cach height three times, and take the average • Choose the snapshot of eloser spectrum to the average to put in your report Add water to the next graduation of the thin rod and repeat the previous steps. • Put in a table the heights, and for each height put the different measurement of frequency and their average. Use , for the frequency of empty glass. Plot the frequency as function of the height h. • Describe and comment the curve. Theoretical investigation Explanation of the sound • By analogy with the sound produced in a string as treated in the course, explain qualitatively the sound produced by the glass showing the source of:
The elastic force The inertial parameter Explain why the frequency changes with the quantity of water in the glass. • Determine some parameters of the glass and the liquid in the glass, responsible of frequency change Boundary conditions and standing waves What should be the boundary condition for a propagation of mechanical wave along a circle (upper rim of the glass)? • Describe the different modes of oscillation showing where will be located the nodes and antinodes for some harmonics along the upper rim of the glass. Use drawing for some harmonics to clarify your idea. Boundary conditions and standing waves Many articles investigate sound vibration in glass showing a relation between the frequency f, the height of water h, an the total height of the glass # given by (*)** 1+AⓇ)* • Search an article in the Internet describing the above relation Using the data measured experimentally, fit (?) as function of and determine the deviation from theory Optional work • Use another liquid with higher density than water and notice the change of frequency with the density of the liquid Optional work Based on articles published about the subject, describe the principle of theoretical study leading to the equation describing the frequency as function of liquid height in the glass.