1. What is Sound?? n “If a tree falls in the forest and no one is there to hear it, does it make a sound?” n There are 2 ways to answer this: n Objectively n Subjectively

2. Sounds Objective View n Depends on external evidence n Form of energy n Use of numbers n Involves λ, f, & v Subjective View n Depends on someone's point of view n Is it observed and recorded? n Listen for harmonics n Perceived as music vs. noise

3. Requirements 1. Source - a vibration of some kind ex: {This is where you raise your hand} 2. Medium - sound needs particles to move ex: air, liquid, solid 3. Receiver - an interpreter of the waves produced ex: Ear

4. Frequency Levels n Human Ear can hear sounds between 16 Hz -20 000 Hz n Infrasonic n Ultrasonic n Uses of Ultrasound n (again, this is where you raise your hand!!)

5. Sound Characteristics ¶ Quality - waveform complexity òpure tone òovertone òrecurring pattern · Pitch - the frequency of the sound wave íOctaves ¸ Loudness - the amplitude of the sound wave Ôan analogy is that the large water waves have more energy than smaller water waves Ô- surfs up dude!!!!

6. Speed of Sound n Speed of Sound varies depending on how the particles are vibrated. n In solids, particles are closer and easily vibrate, consequently sound travels best in solids.