Make a cone using a poster paper or cardboard and adhesive tape. Cover a mobile phone that is playing music with the cone. Compare the loudness of the sound with and without the cone. You can also use another mobile phone with an app to measure the characteristics of the sound in both cases. Try experimenting with different shapes and record your observations.
To perform this activity, I made a cone using poster paper and adhesive tape. I placed the cone over a mobile phone playing music and compared the loudness of the sound with and without the cone.
Observation with the cone: When the cone covered the phone, the sound was noticeably louder in the direction the cone was pointing. The cone directed the sound waves forward, concentrating them rather than allowing them to spread in all directions.
Observation without the cone: Without the cone, the sound dispersed uniformly in all directions, making it sound less loud at the same distance.
Using a sound measurement app: I used another mobile phone with a sound measurement app to record the decibel levels in both cases. The reading was higher when the cone was used, confirming the increase in loudness.
Experimenting with different shapes: I also tried using a wider cone and a cylindrical shape. The narrower cone concentrated the sound more effectively, producing greater loudness in a specific direction. The wider cone spread the sound over a larger area but with less intensity. The cylindrical shape provided moderate concentration. This activity demonstrates how shape affects the direction and concentration of sound waves.
Explanation
The textbook asks students to perform a hands-on activity to understand how the shape of a cone affects sound loudness. The cone acts as a sound director, concentrating sound waves in a particular direction rather than allowing them to disperse. This is similar to the principle behind curved surfaces in concert halls mentioned in the context. Using a sound measurement app (like Phyphox mentioned in Activity 10.7) allows for quantitative comparison. Different shapes produce different results because they direct sound waves differently - narrower cones concentrate sound more intensely in one direction, while wider shapes spread it out.
Solution Steps
Step 1: Make a cone using poster paper/cardboard and adhesive tape
Step 2: Play music on a mobile phone and cover it with the cone
Step 3: Compare loudness of sound with and without the cone
Step 4: Use another mobile phone with a sound measurement app to record decibel levels in both cases
Step 5: Experiment with different shapes (wider cone, cylinder) and record observations about how each shape affects sound concentration and loudness