Question

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. (This activity is to be facilitated by the teacher.)

Answer 1

The cone reflects and directs sound energy forward, so the sound appears louder in front of the cone than without it. The sound becomes more directional, while behind the cone it is softer. Using a sound-measuring app, the decibel reading is higher in front of the cone and lower on the sides or behind it. A long, narrow cone focuses sound most strongly, while a short, wide cone spreads it over a wider area. Observations should record how loudness changes with cone shape, size, and direction.