Musical Pipes: Difference between revisions

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== Age ==
{| class="wikitable" style="color:black; background-color:#ddd; margin-left: auto; float:right"
| [[Physics]]:
| Sound Waves
|-
| Grade Range:
| [[Elementary School]], [[Middle School]]
|-
| Format:
| [[Hands-on]]
|}


Elementary School, Middle School, High School
The Musical Pipes are a great demonstration to set out and let students play with. Consider bringing extra paddles with you for students to share!
 
== Format ==
 
Stage Show,Hands-on


== Materials ==
== Materials ==


    Musical pipe instrument
* Musical Pipes (Small set or Big set)
    Posters (optional)
* Paddles: Foam sandals, leather paddles, etc.
    “Soft” object to hit top of pipes with - flip flop (optional)
    Slinky (optional)


== Safety Precautions ==
== Safety Precautions ==


Science Theatre demonstrators must keep the safety of themselves and their audience in mind at all times. All Science Theatre demonstrators must have read through the Safety Training page. The ST Safety Box with first aid kit, fire extinguisher, etc. should always be available to demonstrators. Always wear safety gloves, glasses, and a labcoat if handling chemicals; always perform potentially dangerous demonstrations at a safe distance from the audience; and always keep a very close eye on any volunteers you call from the audience.
Please read the General Safety Precautions section of the [[Demonstration Safety]] page before performing this demonstration.
 
Keep ears away from tube openings. Don’t hit the tubes too hard with your hands.
 
== Preparation ==
 
Bring the instrument to where the demo will take place.


== Demonstration ==
== Demonstration ==


Hit the tops of the tubes with your hands or the object to make sounds. When you hit the tube, keep your hand on top of it until the sound stops. By covering half the tube with your hand, you can play pitches that are an octave higher. (This is kind of difficult to do, but it is easiest with the shortest pipe.) You can play songs if you like. (See section below) The slinky can be used to help describe/show what a compression wave is (it may be easier to do this on a table or the ground rather than in the air). You hold one end and have someone else hold the other. Move your end a little toward the other person and then back to its initial position. A compression wave should move along it. You can have older audiences calculate the wavelength and/or the frequency of the waves created in each pipe (the equations can be found below).
# Set out the Musical Pipes and let students play with it. Provide Explanations as you see fit.
 
# For older students, you can provide them with the information on calculating the frequency of the wave, and have them measure the individual tubes to calculate the frequency.
== What to Say ==


When you hit the top of the tube, your hand causes the air to compress inside the tube. The tube helps to focus and direct the air compression. This air compression is known as a sound wave, which is a type of compression wave. (You can use the slinky demo here if you want. Try holding it vertically next to the pipe to show a perspective like the pipe. This can also be a bit tricky.) Every wave has a certain wavelength. For sound waves, each different wavelength has a different pitch associated with it. Musicians assign note names A through G to different pitches. These are determined by what is known as frequency. Frequency is how many wavelengths pass one point per second. The shortest pipe creates the wave with the shortest wavelength and the largest frequency. This means that it is the highest pitch. The frequency of a sound wave moving through it is about 220 Hertz, which corresponds to the note A (3rd octave).
== Why This Works ==


For older audiences, you can explain the difference between an open and closed pipe. When a pipe is closed on one end, in this case by your hand, the wavelength is equal to four times the length of the pipe because a node (area of zero amplitude) is formed on the closed end with an antinode (area of maximum amplitude) on the open end. The amplitude of a sound wave is given by its pressure. A frequency that is twice the magnitude of another has the same note name but is said to be an octave higher. For the shortest pipe, you get the 220 Hz frequency as said above. By covering only half of the top of the pipe with your hand, it is the equivalent of an open pipe. With an open pipe, the wavelength is only twice the length of the pipe because an antinode is formed on each end. For the shortest pipe this would correspond to approximately a 440 Hz frequency which is also the note A (but of 4th octave).
''Sound Waves'' are a type of pressure wave that we can hear. When we hear a sound, our ears are actually picking up on a vibration that is traveling through the air. When one end of the tube is slapped with a paddle or a hand, it sends a vibration through the tube which we hear as an audible sound. By having the tubes cut to certain lengths, we can change the ''Frequency'' of the wave, or the note that is made. A shorter tube will create a higher note, while a longer tube creates a lower note.


== Why It Is ==
The frequencies of the waves generated in the tubes can be calculated by using this equation:


When air is compressed and sent through a tube, it becomes a compression wave with a wavelength determined by the length of the pipe that the air is moving through. Each length tube gives a different wavelength and, therefore, a different frequency. Different frequencies correspond to different musical notes. Different wavelengths are also found in open vs. closed pipes (see above figure). When your hand completely covers the top of the tube, it acts like a closed tube. This would mean that there is a node at the closed end (where your hand is) and an antinode at the other end. There is only 1/4 of a wavelength formed (as seen above), so one wavelength is 4 times the length of the pipe. By only covering half of the top, the tube acts as an open tube, and you get antinodes at each end. This allows for 1/4 of a wavelength to fit in the length of the pipe meaning the wavelength is twice the length of the pipe.
{| class="wikitable" style="color:black; background-color:#ddd; text-align: left; right-margin: auto"
| '''''f''''' = '''v'''/'''λ'''
|-
| '''''f''''': Frequency
|-
| '''λ''': Wavelength
|-
| '''v''': Speed of Sound (232 m/s or 1,126 ft/s)
|}


== Real Life Examples ==
In this case, the wavelength will be equal to the length of the tube, so by measuring the tube a student could calculate the frequency for the note they hear. Something that can be noted <!--PUNPUNPUNPUNPUNPUNPUNPUNPUNPUN-->is that all octaves for a given note are multiples of each other. that is, for an A note of 220 Hertz, the next higher octave will be 440 Hertz, and the A note above that will be 880 Hertz. Likewise, the A note below will be 110 Hertz, followed by 55 Hertz.


Any wind instrument


Open pipe: flute
== Additional Information ==


Closed pipe: clarinet
* This demonstration pairs well with the [[Tuning Forks]] and the [[Slinky Waves]]
* Students can connect this demonstration to wind instruments, such as Trumpets, French Horns and Trombones!

Latest revision as of 17:48, 17 August 2016

Physics: Sound Waves
Grade Range: Elementary School, Middle School
Format: Hands-on

The Musical Pipes are a great demonstration to set out and let students play with. Consider bringing extra paddles with you for students to share!

Materials

  • Musical Pipes (Small set or Big set)
  • Paddles: Foam sandals, leather paddles, etc.

Safety Precautions

Please read the General Safety Precautions section of the Demonstration Safety page before performing this demonstration.

Demonstration

  1. Set out the Musical Pipes and let students play with it. Provide Explanations as you see fit.
  2. For older students, you can provide them with the information on calculating the frequency of the wave, and have them measure the individual tubes to calculate the frequency.

Why This Works

Sound Waves are a type of pressure wave that we can hear. When we hear a sound, our ears are actually picking up on a vibration that is traveling through the air. When one end of the tube is slapped with a paddle or a hand, it sends a vibration through the tube which we hear as an audible sound. By having the tubes cut to certain lengths, we can change the Frequency of the wave, or the note that is made. A shorter tube will create a higher note, while a longer tube creates a lower note.

The frequencies of the waves generated in the tubes can be calculated by using this equation:

f = v/λ
f: Frequency
λ: Wavelength
v: Speed of Sound (232 m/s or 1,126 ft/s)

In this case, the wavelength will be equal to the length of the tube, so by measuring the tube a student could calculate the frequency for the note they hear. Something that can be noted is that all octaves for a given note are multiples of each other. that is, for an A note of 220 Hertz, the next higher octave will be 440 Hertz, and the A note above that will be 880 Hertz. Likewise, the A note below will be 110 Hertz, followed by 55 Hertz.


Additional Information

  • This demonstration pairs well with the Tuning Forks and the Slinky Waves
  • Students can connect this demonstration to wind instruments, such as Trumpets, French Horns and Trombones!
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