1. Sound Lab Monday March 12 th, 2012 Warm Up Task: What makes sound?

2. What you need to write on your paper: Lab Station #1: Drumming Lab Station #2: Your throat Lab Station #3: Tuning fork Lab Station #4: Rubber band strung Lab Station #5: Buzzer Lab Station #6: Steel yardstick

3. Lab Directions: Every station will have a bright green paper with simple directions on what to do. Make sure everyone takes a turn, then discuss and answer the question you copied from the previous slide

4. Sound Lab 1.) Describe what you hear, feel, and see. 2.) Did the sound ever change and how did you make it change? 3) What are your overall conclusions about the sound at this station? Questions:

5. Sound Lab cont’ Station # 1- Drumming Question 1 Question 2 Question 3

6. Sound Vibration Is a wave that vibrates particles of matter A rapid back and forth movement Sound Wave Notes

7. How do we produce sound? We use our muscles in our body to push air up our body to push air up from your lungs through a from your lungs through a narrow passage through the narrow passage through the vocal cords, which are actually vocal cords, which are actually folds! folds! The force of air causes them to vibrate That produces sound waves!

8. How does our ears hear sound waves? Vibrations travel though the ear canal (hammer, anvil, and stirrup) Then the sound waves vibrate the eardrum

9. Continued- How does our ears hear sound waves? The eardrum vibrating is detected by the cochlea is detected by the cochlea Then the cochlea sends Then the cochlea sends a message to your brain a message to your brain The cochlea looks like millions of little hairs inside ear fluid Do ear cup example http://www.youtube.com/watch?v=tkPj4IG bmQQ&feature=related

10. So then, Why is there not sound in space? Space is a vacuum, which means empty space or very few particles Sound has to vibrate matter or a medium In space there is no ‘air’ or medium for the wave to vibrate, thus no sound can be produced In space there is no ‘air’ or medium for the wave to vibrate, thus no sound can be produced

11. What affects the speed of sound? Temperature and medium effects the speed of sound.

12. Speed of Sound in Different Mediums If the mediums are all 20 degree C then the following is true... In Air-Gas sound waves travle at 344 m/s In Water-Liquid 1,400 m/s In Steel-Solid 5,00 m/s

13. Speed of Sound in Different Temperatures If you are in the dessert and in it 115 degrees F sound will travel faster, then if you are in the arctic and it is -20 degrees F! Why? At higher temperatures particles more faster. So if sound waves push against the already fast moving particles, then it will quickly pass through and vibrate the already fast moving particles. Hall way example

14. Frequency A given number of waves in specific amount of time, which determines the pitch. The pitch is a characteristic of high and low sounds. Frequency is measured in hertz.

15. The Doppler Effect The Doppler Effect is a change in the perceived pitch when the source of the noise is moving. So to further explain: All waves, light and sound, travel out from the source, but when the source is moving the waves get bunched closed together making a higher frequency/pitch and the waves trailing behind become spread out making a lover pitch/frequency http://www.youtube.com/watch?v=Kg9F5pN5tlI

16. Amplitude Amplitude is Amplitude determines intensity, which is just how loud sound is. Intensity of sound is measured in decibels (dB).

17. Decibels (dB) Examples: 10 dB Leaves Rustling 30 dB Whisper 60 dB Dog Barking 90 dB Motorcycle 140 dB Firecrackers