How to Focus Sound Waves

Sound waves don't travel through solid objects as well as you might think. When an object vibrates, it influences the oxygen molecules around the object to make sound waves. When you place a solid object near the vibrating object, the sound vibrations rebound off the solid object and head in the opposite direction. Building a half dome shaped object around the source of the sound directs the sound waves away like a beam. Directing sound waves can make a sound more intense without increasing the volume.

Things You'll Need

• Half dome construct

Instructions

1. Set the object that will make the noise on a flat surface. Position the object so the part that produces the noise (for example, a speaker) faces in the direction you would like to direct the noise.

2. Set a half-dome-shaped construct behind the source of the sound. The dome must be large enough to accommodate the source of the sound without touching it. Tuck the source of the sound into the dome construct.

3. Allow the source of the sound to start vibrating. The sound waves will bounce around the walls of the half dome construct to exit through the opening of the dome.

4. Stand in front of the dome construct to gauge the clarity and volume of the sound. Walk around the back of the half dome construct to gauge the volume from behind the construct. The volume should sound muted behind the construct.

5. Rotate the half-dome construct around to change the direction of the sound waves. Rotate the source of the sound with the half dome shape.

References

• Collin Wells; El Dorado Springs Drama Department; El Dorado Springs, Missouri
• Ronald Alumbaugh; El Dorado Springs Music Department; El Dorado Springs, Missouri