Sound Reflection and Sound Absorption

REFLECTION OF SOUND The reflection of sound follows the same laws as the reflection of light ◦Angle of incidence=Angle of Reflection Sound waves can be reflected by hard/solid surfaces. ◦Example: Walls, Buildings and Cliffs

REFLECTION OF SOUND Echoes are produced by the reflections of sounds from such surfaces.

REFLECTION OF SOUND

REVERBERATION Reverberation occurs when the original and reflected sounds are so close that the two cannot be heard as separate sounds. The original sound just seems prolonged

REVERBERATION Another way of looking at it is it is the prolonged sound due to the merging of many echoes. ◦Example: Thunder!!!!

REVERBERATION

SOMEONE TURN THE MUTE BUTTON ON FOR THAT KID!!!! There are a few students that are very loud in the class. No matter how much I, ask them, they keep talking and talking. So instead of asking them to stop repeatedly, could we just make something to put over their head to absorb the sound they make?

SOMEONE TURN THE MUTE BUTTON ON FOR THAT KID!!!! Before you are the following items; ◦Box ◦Foam ◦Wood ◦Saran Wrap ◦Tin Foil ◦Plastic Bottles ◦Cardboard ◦Paper Towels

SOMEONE TURN THE MUTE BUTTON ON FOR THAT KID!!!! Your job is to create a noise helmet to block out their constant talking. The team who’s box allows the least amount of sound to transmit through the box win! Use the lab sheet as a guide. Answer the questions as you go along.

Absorption of Sound Everything, even air, absorbs sound. One example of air absorbing sound waves happens during a thunderstorm. When you are very close to a storm, you hear thunder as a sharp crack. When the storm is farther away, you hear a low rumble instead. This is because air absorbs high frequencies more easily than low. By the time the thunder has reached you, all the high pitches are lost and only the low ones can be heard.

Absorption of Sound The best absorptive material is full of holes that sound waves can bounce around in and lose energy. The energy lost as heat is too small to be felt, though, it can be detected by scientific instruments.