The Chemistry of Harmonicas, Accordions, and Theremins

Mechanics of the harmonica“Music is an art and a passion. It is something that can be enjoyed by almost everyone, and created by almost everyone. It affects our thoughts and affects emotions, but how does it work? What chemistry lies behind the beauty: behind the strings of a guitar and the head of a drum; behind the bell of a trumpet and the reed of a saxophone; behind the bow, gracefully gliding across the strings of a violin?” While the last few blog posts about music and chemistry have focused on the guitar, the drums, and the cymbals, this blog post will briefly describe the chemistry behind accordions, harmonicas, and theremins; each being a unique instrument with very variant sounds.

Harmonicas

The harmonica is the number one instrument for travelers. Its rich sound is also adored by many blues musicians. Harmonica is a free reed wind instrument. What that means is the reeds of the harmonica is attached only at one end, and is put to vibration by blowing into the instrument.Basic assembly of a harmonica

The reeds of a harmonica are usually made of brass, stainless steel or bronze. The shape and weight of those reeds determine the pitch of the instrument. If the reed is heavy and flexible, it produces a low-pitched sound. On the other hand, if the reed is light and stiff, it produces a high-pitched sound. This is because the comb of the harmonica has an opening which the reed covers, and the vibration of the reeds causes them to undulate in and out of the gaps of the comb, blocking and letting in air through the comb as the result. This is how the harmonica is able to create the sound. Since heavy and flexible reeds vibrate at a slower rate than light and stiff ones, the frequency of the vibration is lower, hence a lower pitch, and vice versa. This site goes into more detail about how the harmonica produces sounds, whereas this site shows the manufacturing materials and process for producing harmonicas.

Here is a video of Billy Joel performing Piano Man. Take note of the interesting sound that he can create using a harmonica.

 Accordions

An accordionThe accordion is also a reed instrument that has a keyboard. When the keys are pressed, the metal reeds vibrate, which create sound. These free-standing reeds produce sound in a method similar to the harmonica, illustrated above. The length and thickness of the reed determines the pitch of the note it produces. Long reeds produce lower notes than shorter reeds. The frame and most other parts of an accordion are made of poplar wood. This kind of wood is useful because it is sturdy and lightweight.

The mechanics of an accordion

If you want to hear the sound of an accordion, view this following video, which shows a couple of French songs being played by an accordion. You might want to turn down the volume (Not because it sounds bad, but because it’s loud). If you want to read more into the history of accordions, check this out. This link shows the amount of work and precision that goes into producing an accordion.

Theremin

The theremin was by far the most interesting musical instrument for it’s time; running only using electrical energy, instead of using mechanical energy, it was the first electronic instrument created. The concept was discovered by Léon Theremin, who had been tinkering with an oscillating circuit. He found that moving his hand in and out of the electric field generated by said radio frequency oscillator changed the frequency it produced. This was due to the human body having a natural capacitance (the amount of electric charge it can hold), which interfered with the electric field. This is more on the physics side of things, but if you are interested in electric fields and potential, this is a great place to start. Theremin, being a cellist, instantly went to work on creating an instrument using this knowledge.

 Watch the video above to see the magic in action; it seems almost unreal, doesn’t it? However, while it seems like magic, there is a thorough explanation to why this eerie instrument works, and the best person to explain would have to be the maker himself!

“By using an alternating current of suitable frequency, tones of varying pitch are easily obtainable. A small vertical rod is used as the antenna. When the instrument is in operation, electromagnetic waves of very weak energy are generated around this rod. These waves are of a definite length and frequency. The approach of a hand, which is an electrical conductor, alters the conditions in the electromagnetic field surrounding the antenna, changes its capacity and thus affects the frequency of the alternating current generated by the apparatus. In this manner, a kind of invisible touch is produced in the space surrounding the antenna, and, as in a cello, a finger pressing on a string produces a higher pitch as it approaches the bridge, in this case also, the pitch increases as the finger is brought nearer the antenna.

Likewise, the intensity of the tone can also easily be changed by a simple movement of the hand in space. For this purpose the instrument is equipped with another, in this case circular, antenna around which electromagnetic waves are similarly formed. The approach of a hand toward this antenna causes a change in the degree of the intensity of the alternating current which produces the tone. Thus by raising the hand over the ring-shaped antenna the note sounded grows louder and by lowering the hand it grows softer, until it dies out in the softest pianissimo.” – Leon Theremin

If you want to see Leon Theremin play his own instrument, check out the video below.If you’re interested in theremins, you can build one for yourself at home! In fact, check out this website, which shows projects people have made with theremins.

Conclusive Remarks

We’ve covered a lot of material in the past few blog posts. Hopefully we’ve sparked your interest in chemistry, especially in music. Music brings the human world together, and chemistry is the language through which everything happens. Whether it be through the corrosion of guitar strings, the drum head materials, the alloys in a cymbal, the effects of different frequencies on the brain, the way humans produce vocal sounds, or how accordions, harmonicas, and theremins work, chemistry is everywhere. If you enjoyed reading these, we recommend you check out all the others written by other authors. Have fun!

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