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I need to do a science project, and I'm investigating how temperature affects the pitch of an instrument. I currently play clarinet, and I'm not comfortable putting my wooden clarinet in the fridge or using a heater to drastically change the temperature around the wood (I don't want to absolutely ruin the wood or risk cracking it). Instead, I'm going to use a recorder (probably buy one off of Amazon) but I need an instrument that will show a strong change in pitch when heated or cooled. I know that any wooden recorder will show this, but will a plastic recorder also show a strong enough change?

Wooden recorders are also a lot more expensive so I would prefer to use a plastic one, but I'm just not sure that it would suffice.

Rice Pudding Whale
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    It wouldn't be much of an experiment if we told you the result in advance. – Aaron Jun 22 '21 at 07:22
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    "I need an instrument that will show a strong change in pitch when heated or cooled" - That's not an experiment, that's merely verification. A true science project tests a hypothesis and the science is valuable whether it confirms or refutes the hypothesis. Formulate your hypothesis (the recorder will change in pitch when heated/cooled), test it, and report your results. Whether they are positive or negative results has no bearing on how well you are doing the science. – Todd Wilcox Jun 22 '21 at 07:27
  • Humidity change often goes along with temperature change, and wood will react rather differently compared with plastic, so it probably won't be a fair experiment anyhow. Pre-loved wooden recorders come along at a couple of pounds in charity shops, et al. Most likely less than a new plastc one! – Tim Jun 22 '21 at 07:29
  • If you really want to do science, your next step is to research the thermal expansion coefficients of plastic and wood and then calculate the exact predicted expansion or contraction of the instrument(s) in question, and then study the acoustic properties of the instruments to calculate how much a deformation will change the pitch and then run the experiment to see if your calculations are correct. Don’t ask here what will happen - it’s your job as the scientist to predict it! – Todd Wilcox Jun 22 '21 at 16:15
  • Regardless of the instrument you use, have you tested how well you can produce a repeatable constant pitch with a recorder (or a fine clarinet for that matter) at any temperature? It seems possible your embouchure will introduce errors greater than temperature-induced variations. – Theodore Jun 22 '21 at 21:37

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If you use a plastic recorder, you'll be investigating how temperature affects the pitch of a plastic recorder! That's OK.

And temperature WILL affect the pitch. Just make sure you measure its physical dimensions as well as the pitch at different temperatures. You wouldn't want to attribute any change of pitch to the wrong thing!

Laurence
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This is almost more a science question than a music question. But yes, I think a wooden recorder would be a better choice than plastic, and they're not terribly expensive; they can be had for less than $20 (and even those, in my experience, sound better than similarly-priced plastic ones). It's also interesting to me that you're suggesting subjecting the instrument to more extreme temperatures than would normally be encountered. As a violinist, I would refuse a gig that required me to play outdoors at temperatures below, oh, 45 degrees F or above 80 (I guess... I wouldn't be too happy about the 50s or high 70s either!). If any instrument is going in a freezer or an oven, the experiment might stop being about the effect on pitch and start being about the instrument's ability to avoid damage.

The experiment is a great idea, and there's no reason not to proceed, but to really measure the factors that impact pitch would take very precise measurements of many different factors. You would need to measure not just the outer but inner diameter of the recorder (bore) across all its length; you'd have to measure any gap at joints; you'd need very accurate measurement of the temperature of the air inside the instrument (and, if the experiment is meant to measure realistic use, the impact that warm human breath has on a cold instrument). The recorder is a good choice for keeping it simple; if it were, say, a harpsichord, you'd also be measuring string tension!

Andy Bonner
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The main temperature factor affecting the pitch of a woodwind instrument will be the density of the air itself. So the material doesn't necessarily matter that much.

The speed of sound changes with temperature, which affects the frequency of the standing waves that form in the chamber of the instrument. You can see from this graph that between 0 and 100°C.it varies from about 335 m/s to 395 m/s (in dry air: there are more confounding variables like humidity). That is about 18% faster.

Let's assume that your recorder doesn't expand very much between 0 and 100°C, so that the standing wave for a given note has about the same wavelength. That wave is traveling up and down the tube 18% faster, and so the frequency must be 18% higher, which is almost 3 semitones. Even if the instrument expands, that is going to be insignificant compared to this difference.

Kaz
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