Sound Waves Palm Pipes Objective Students will be

Sound & Waves Palm Pipes

Objective Students will be able to create vibrations, which we hear as music, in order to understand basic properties of sound and waves.

Warm up Using the slinky on your table, demonstrate the movement of a sound wave. Now demonstrate the movement of a light wave.

Focus Questions What are some important properties of sound waves? What is resonance and why is it important? What is sound and how do we hear it? What is music and how do we make music?

Exploration Palm Pipes http: //www. stevespanglerscience. com/img/cache/02268 c 260 f 8 fff 6 f 7502 dd 93 a 20 e 39 be/WPVC-100_2. jpg

Palm Pipes Check to see the note of your palm pipe. Follow along with the music and play your palm pipe when your note occurs.

Mary Had a Little Lamb Melody E D C D E E ED D D E G G (1 st line) Melody (2 nd line) E D C D E E D D E D C

HAPPY BIRTHDAY Melody C C D C F E Harmony A A Bb Melody C C C A F E D Harmony F C Bb C C D CGF Bb Bb A F G F C A

Jingle Bells Melody E E E E G C D E Harmony F F F E E E D D E D G Melody E E E E G C D E Harmony F F F E E G G F D C

GOD BLESS AMERICA Melody F E D C Harmony A C Melody E C E F G C Harmony C E G A Bb D E F Bb A C F G A Harmony Melody G F G A D G F E F F E C F GA C G A Bb E A Bb C D E F Melody D C Bb A G F Harmony F F E C E D F F E C G

TWINKLE, TWINKLE LITTLE STAR Melody F F C C D D C Bb Bb A A G G F Harmony C C A A Bb Bb A G G F F E E C Melody C C Bb Bb A A G Harmony A A G G F F C Melody F F C C D D C Bb Bb A A G G F Harmony C C A A Bb Bb A G G F F E E C

Explanation How could pipes that have the same note be different lengths?

Explanation How does it work? When you pound the Palm Pipe into the palm of your hand, it disturbs the air molecules inside the tube. The action of these molecules creates the vibration that becomes the note you hear. The different lengths of pipe create different lengths of sound waves, which in turn create eight different notes.

Explanation Click this picture for the online wave animation.

Explanation http: //www. passmyexams. co. uk/GCSE/physics/images/long_waves. jpg

Explanation Wavelength is the distance from the crest of one wave to the crest of the next. Frequency is the number of waves that pass a point in each second. Amplitude this is the measure of the amount of energy in a sound wave. http: //www. fi. edu/pieces/dukerich/vibrations/graphics/wavedi. gif

Explanation This is how a high and a low soundwave looks. A bird makes a high pitch. A lion makes a low pitch. Can you think of other high and low pitched sounds?

Explanation Basic characteristics of standing waves Node Points where the string does not move Anti-node Points where the string moves the most

Explanation RESONANCE A condition where a force (a push) occurs at a frequency that results in a Standing Wave These Standing Waves occur at what are called Natural Frequencies or Harmonics. Every object, substance and material has its own Natural Frequencies, where they “like” to vibrate.

Explanation FREQUENCY x WAVELENGTH Each Harmonic has a different frequency and wavelength Frequency x Wavelength gives the same answer for ALL Harmonics Cycles/Seconds x Meters/Cycle= Meters/Second which is a value for speed of the Wave on the string If Frequency increases, Wavelength decreases and if Frequency decreases, Wavelength increases

Explanation Sound Waves How do we perceive Sound Waves? What do they have in common with other kinds of waves? What is different about Sound Waves?

Explanation Sound and Music - Chords Different notes have different frequencies. Chords are combinations of different notes with specific mathematical relationships. Different relationships of the notes will produce chords with very different “moods” or “feel. ”

Explanation Musical Instruments Musical instruments play different notes Frequencies are controlled by altering wavelength Vibrating materials like strings or reeds cause chunks or columns of air to vibrate

Explanation Musical Instruments Natural Frequencies/Harmonics cause amplification through Resonance Instruments can be amplified this way and/or electronically The vibrating element vibrates at ALL its Harmonics, not just the Fundamental. The combination of these frequencies give an instrument its particular sound.

Elaboration Important numbers: Speed of sound in air at room temperature = 350 m/s. Speed of light in a vacuum (in outer space) = 299, 792, 458 m/s or 3. 0 x 108

Frequency calculations Velocity of a sound wave is equal to its frequency times its wavelength. v = f x λ 1. wavelength can be obtained by multiplying the tube length in meters by 4 2. velocity is 350 m/s in normal room air temperature 3. So…if you divide 350 m/s by a tube's wavelength value, you obtain the approximate frequency in cycle per second, or hertz, of the note the tube will produce. Example: 350 m/s tube length of 21 cm (. 21 m) x 4=. 84 m = frequency of 416 Hz

Frequency calculations: Now calculate the frequency of the Palm Pipes assigned to the members of your group and be prepared to share your answers with the class.

Approximate answers: Note Length (cm) Frequency (Hz) F 1 23. 6 349 G 1 21. 0 392 A 1 18. 7 440 B flat 1 17. 5 446 C 1 15. 8 523 D 1 14. 0 587 E 1 12. 5 659 F 2 11. 8 698 G 2 10. 5 784 A 2 9. 4 880 B flat 2 9. 2 892 C 2 7. 9 1046 D 2 7. 0 1174 E 2 6. 2 1318 F 3 5. 9 1397

Closure In your notes, write a brief summary of what you have learned.