The document summarizes an experiment that tested the effectiveness of different common materials for sound insulation. The materials tested included expanded polystyrene foam, stainless steel, wood, and paper. The experiment measured the sound reduction index and transmitted coefficient of each material at different frequencies. The results showed that stainless steel was the most effective at sound insulation, while expanded polystyrene foam and paper were the least effective. Common soundproofing techniques for homes using different materials were also discussed.

1. An Experiment On Effectiveness of different materials on sound insulationCC2007 Environmental Science (Group Presentation)Group Members:Wong Wai Sum , Sum (09081555A)

2. Li Hong Bin , Ben (10034164A)

3. LukWai Man , Ray (10094530A)

4. Lau CheokHei, Jeff (09090889A)

5. KanKaHim , Ken (10022177A)ContentBackground IntroductionExperiment ObjectiveExperiment ProcedureResult AnalysisFurther developmentQ & A

6. What is noise?Noise can be a very Loud soundLow-level sound but annoying

7. Loud Noise in Hong KongThe main concern of noise :Traffic NoiseIt affects more than one million people655 roads generate noise greater than 70 dB But only 101 of these roads applied barriers

8. What can we do personally?Choose some good sound insulating materials to build your flat.Today, we are going to test which materials (commonly seen in our daily lives) are good at insulating sound !

9. Sound Insulation ExperimentObjective To compare the sound insulation ‘s effectiveness of different materials under different frequencies in term of Sound Reduction Index(R) and Transmitted coefficient (T).

10. Materials to be tested…(1)the Expandable Polystyrene (EPS) foam(2)stainless steel(3)wood(4)A4 paper

11. What is sound??Sound is a mechanical wave also a kind of longitudinal wave which does not have Polarization(偏震)produced by vibrations of objectsrequire medium for propagation example: air, watercannot travel in vacuum

12. Where the sound from?Can be found easily in our daily lifeFor example,Musical instrumentCarTalkingAircraft take-off

13. Sound InsulationInsulate the sound we don’t want to hearThe ability for the material to reduce the sound energy transmitted into an adjoining air space.Type of sound insulation:Airborne Sound InsulationImpact Sound Insulation

14. Airborne Sound Insulationthe insulation against noise originating in air, e.g. voices, music, motor traffic, wind.Impact Sound Insulationthe insulation against noise originating directly on a structure by blows or vibration

15. Insulated the sound by mean of …reflectionabsorptionSound would reflect at the surface of material so that only a part of sound energy will be transmitted. Also, material will absorbs the sound energy and dissipates in form of heat making the reduction of transmission of sound.result in reduction in sound level

16. Decibel meterusing a decibel meter, we can measure the sound level (in dB) of different sound source. sound level (L) L = 10 log10 [ I/I0 ]…………………(1)sound reduction index (R): R = 10 log10 [ 1 / T ] (dB)…………(2) T: Transmitted sound energy / Incident sound energy

17. Sound Insulation ExperimentApparatus:

18. Dimension of the shoe box = 29cm x 19cm x11cm = 6061cm3

19. Area of the opened part = 19cm x 11cm = 209cm2Frequencies chosen:

20. Materials used:Sound Insulation ExperimentProcedure:Cut out one side of the shoe box and place the cloths inside the box.Set up the apparatus following the sequence from A to D as shown in Fig. 1.1.

21. 3. Turn on the speaker and generate a frequency of 125Hz (f1).4. Measure the sound level (L0) using the sound meter and record it in Table 1.1.5. Put the Expandable Polystyrene (EPS) foam (material 1) in front of the shoe box to cover the opened part of the box.6. Measure the sound level (L1) for three times using the sound meter and record them in Table 1.1.

22. 7. Repeat steps 2 to 5 for the remaining measurements using other frequency and material.8. Calculate the average sound level (Laverage= (L1+L2+L3)/3), Sound Reduction Index (R) and transmitted coefficient (T) for different material under different frequency using equation (2).9. Draw bar charts to show the relation between R/T and different frequencies for different materials.

23. Result and Discussion:

24. So, the greater the R, the greater the Sound Reduction Level is.

25. So, the smaller the T, the greater theSound Reduction Level is.

26. Analysis:Assumption:

27. The unique sound source for the experiment is the frequency generator.

28. The background noise during the experiment is kept constant.

29. The reflection and refraction effects of sound are negligible.Sources of error:

30. Unstable readings of decibel meter

31. Impact sound can transmit through the ground to the box due to the vibration of speaker.

32. For the sound transmitted through the material , the sound wave can be reflected inside the shoe box, which may be noise, and it may affect the reading.The background noise may not be constant though out the experiment.

33. Maximum possible error of the measurement = 0.05dB x 2 = 0.1dBIn Our ExperimentConclusion:The greater the R, the greater the Sound Reduction Level is. ( R↑->Reduction Level↑)The smaller the T, the greater the Sound Reduction Level is.( T↓-> Reduction Level↑)The most effective sound insulation material :Steel board (2mm)The least effective sound insulation material :EPS foam (18mm), A4 paper - 50pcs (5mm)

34. Some Professional Insulation Materialsfeatures & benefits:high performance soundproofing material for reducing airborne noise.

35. may be used behind drywall in wall and ceiling assemblies or sandwiched between existing and new drywall.

36. use in flooring systems to increase sound transmission class.

37. used for both residential and commercial soundproofing applications.QUIET BARRIER® HDSuperior soundproofing material for blocking noise for residential and commercial use.

38. features & benefits:cost-effective, low-profile sound blocking barrier

39. designed to reduce noise transmission in wall, floor & ceiling assemblies

40. replaces lead sheeting

41. available in sheets, rolls and "peel & stick" versionsQUIET BARRIER® MDEconomical soundproofing material for blocking noise for residential and commercial use.

42. Comparison on QUIET BARRIER® HD & QUIET BARRIER® MD