Download Musical Straws

Musical Straws
Grade Four
Strand: Understanding Matter and Energy
Topic: Light and Sound
Expectation
4s26 Investigate, through explorations, ways in which different properties of materials,
including their shape, affect the nature of sound.
Materials
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Scissors
A straw (unwrapped)
Audience
Procedure
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Flatten the last inch of the straw with your teeth, making sure that you do not curl the
end (the flatter the better).
Cut the corners off the straight, flattened end of the straw.
Place the end of the straw into your mouth, seal your lips around it and blow until a
sound is produced.
If a sound does not appear right away you may need to re-position the straw (this is a
double reed mouthpiece, like an oboe).
Cut small sections off the bottom of the straw while you are making the sound.
Listen for the changes in the pitch as you cut the straw shorter and shorter.
Predictions
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Predict whether the sound of blowing into a straw will be higher or lower as you make
the straw shorter.
Conclusion
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What is the relationship between the length of the straw and the pitch of the sound?
Which instruments of the orchestra use a reed to produce a sound?
To which section of the orchestra do these instruments belong? (brass, string,
woodwind, or percussion?)
How do these instruments produce different pitches?
Explanation
When the length of the straw is properly flattened, the straw will vibrate as air flows
over it. The vibration is passed on to the column of air inside the straw. This occurs in double
reed instruments (also known as the woodwind instruments in an orchestra).
The vibrating reed produces the oboe-like sound in the straw which varies depending on
the length. By cutting off the end of the straw you continuously alter the length of the air
column and change the pitch. Other instruments that rely on these principles are the English
Horn, oboe, clarinet, and bassoon. The difference is that these instruments however change the
length of the column of air with holes, stops and pads.
Variations
You could also find two straws, one smaller than the other (the smaller should fit snugly
inside the larger straw). Using the smaller straw, repeat Step 1 above by cutting the straw. Slide
the bigger straw up over the smaller straw and start blowing. Move the larger straw back and
forth to change the pitch of the sound. You have now made a straw trombone!
References
Chudyk, M. (2006). Matter and Material Series: Light and Sound. S and S Learning Materials,
Napanee, Canada.
Spengler, S. (2008). Musical Straws. Retrieved October 24, 2008, from Steve Spengler Science
Website: http://www.stevespanglerscience.com/experiment/00000150.
Video: You Tube. Retrieved On October 28, 2008, from
http://www.youtube.com/watch?v=GyXw6u6fBxM&feature=related
Presenters: Anastasia Pasiak-Bellini and Samantha Simpson