1. Discuss this riddle with your partner:  How can a musician playing a single note on a horn change that note without changing the way he or she plays that note?  If the musician plays the same note while moving toward or away from a stationary listener, the note heard by the listener will indeed change -- even if the musician does nothing different.  How can a musician playing a single note on a horn change that note without changing the way he or she plays that note?  If the musician plays the same note while moving toward or away from a stationary listener, the note heard by the listener will indeed change -- even if the musician does nothing different.

2. Doppler Effect When a siren moves toward you, the pitch sounds higher than when it moves away. This change is called the Doppler Effect. Sound waves that move toward you are compressed and have a higher frequency while those moving away are stretched.

3. Who does the pitch change for? The driver? NO! Observer 1? Yes, she hears a higher pitch Observer 2? Yes, he hears a lower pitch

4. How do we make and hear sound? Partner A- research and take notes on how we make sound on page 40- 41. Record your notes in the note taking box for 2-1. Partner B- research and take notes on how we hear sound on pages 62-63. Record your notes in the note taking box for 2-4. Quality notes must… -be in outline form -be neat and organized -include at least 4 facts

5. How we make sound Vocal cords are ligaments that stretch across the larynx. When air passes over closed vocal cords, they vibrate and make sounds.

6. How we hear sound

7. Fanny/Greta says goodbye:( I’ll miss you guys…