2. Methods

Procedures

1. Set up the experiment as shown in Figure 1. With the height of the box as 18 cm, the length as 20 cm and width as 15 cm
2. Connect the phone and produce a sound of 2,000 Hz
3. Use decibel sensor/ sound sensor to measure and record the loudness of the sound without material as L1
4. Place the material ,with a height of 18cm, the length of 20cm and width of 0.4cm in the slot and cover it up with the lid
5. Use decibel sensor/ sound sensor to measure and record the loudness of the sound as L2
6. Calculate the change in loudness of the sound using L=L1-L2
7. Repeat steps 2 to 6, for 2 more times
8. Calculate the average change of the sound
9. Repeat steps 2 to 8 with the remaining materials.