# Pipe Lengths

### Hands On:

1) Try using a mouthpiece without connecting it to any pipe or tubing.

2) Connect different lengths of pipe or tubing to a mouthpiece.

3) Do the sounds that you create with the different lengths of pipe sound different? Can you describe what changes?

### Simple Explanation:

Sound is produced when objects vibrate back and forth very fast. Those vibrations are translated into the air and your ears sense the air vibrations. Faster vibrations sound different than slower vibrations.

We talk about the speed of vibrations in terms of frequency – how many times the air vibrates back and forth per second. We call the sensation of that frequency pitch. Low pitches (bass guitars, deep baritone voices) have a slower rate of vibration and a smaller frequency. High pitches (flutes, birds singing) have a faster rate of vibration and a higher frequency.

The other way we talk about pitch and vibration is in terms of wavelength. A wavelength is simply how far backwards or forwards the air moves. It can be a strange thing to wrap your mind around but the lower the pitch, the lower the frequency of vibration but the larger the wavelength. And the higher the pitch, the higher the frequency of vibration but the smaller the wavelength. This is why the really low pitched instruments like a tuba are much larger than the higher pitched instruments like a flute. Lower frequencies require a larger object to create larger wavelengths.

So when you attach a longer pipe or tube to the mouthpiece, it creates larger wavelengths that resonate at lower vibrations creating.

### Further Experimentation:

Can you use your ear or a tuner to tune the pipes to a particular pitch? There are lots of free online tuners available at websites such as this one: www.tunerr.com

### Some Math:

The instruments that are created using our mouthpieces and pipes, should more or less follow this equation:

Frequency = SpeedofSound/(4*TubeLengthInMeters)

SpeedofSound = 340.29 m / s

### Further Learning:

http://www.explainthatstuff.com/sound.html

http://www.studyphysics.ca/newnotes/20/unit03_mechanicalwaves/chp141516_waves/lesson51.htm

http://www.physicsclassroom.com/class/sound/Lesson-2/Pitch-and-Frequency