Science Projects on Music and Sound

As a botanist, I often get email that reads something like this actual example:

>Hi. I am an 8th grader doing a science project on how classical and
>rock music affects plant growth. I am having some trouble coming up
>with the research. I was wondering if you had any research or material
>that is related to my project; or even point me in the right
>direction. ANYTHING will help. Thank you very much for your time.

Why can't I find scientific literature on musical appreciation by plants?
Plants have no ears to hear and no brain to process or develop musical taste or music appreciation...so any attempts to show relationships between music forms and growth or other responses have met with total failure in the hands of true scientists. This explains the lack of literature for you to read on the subject.

But what about those few articles and books that do make such claims?
Yes there are some quack "scientists" who have claimed that (in highly flawed experiments) certain kinds of music caused improvements in plant growth...but no such claims have met the rigor demanded for publication in respected journals. Such projects are often labeled "pseudoscience" because they fail to explain the control of critical variables, nor do they specify replication levels, nor do they show actual data or the results of statistical testing.

There really is not much good information about the effect of music on plants because all attempts to do controlled studies on plants and music result in "no difference". Any "differences" between a music treatment and a no-music control (or other-music treatment) in pseudoscience studies can almost always be attributed to some difference in other variables in the project which have not been suitably controlled (light, water, fertilizer, soil type, humidity, etc.).

So, as for the TV shows and trade-books, not all "science" is good science. Beyond seismonasty in species like Mimosa pudica described below, there are no articles on musical appreciation or musical tastes of plants in reputable science journals. Some trade books and even some educational texts and software have given projects on musical appreciation by plants more respectability than is deserved. These are good examples of "not everything you read in print is to be believed."

If plants don't have music appreciation, do they respond to sound?
It is possible for a plant to respond to the vibrations accompanying sounds. A short bibliography at the bottom of this page gives you some references...but to almost "nothing to report." I emphasize again that while there ARE responses to sound/vibration in plants, there is NO controlled study published on the MUSICAL TASTES or MUSIC APPRECIATION by plants in reputable journals.

One plant that responds to sound-induced vibration is Mimosa pudica, also known as the "sensitive plant." Vibrations induce electrical signals across the leaflets of this plant, and cells at the base of the leaflets respond to these action potentials osmotically. This response results in a sharp change in the turgor pressure in these pulvinus cells, and that pressure change, in turn, results in the folding of the blade at the pulvinus. Another pulvinus at the base of the petiole may also respond if the vibration is severe enough. This kind of response is known as seismonasty.

How would this plant respond in terms of growth if its leaves were kept closed by constant vibration? If you think very long about photosynthesis in leaves as the driving force for growth, you will realize that continuous leaflet closure would inhibit rather than stimulate the growth of the plant. Indeed loud sounds (vibrations really) have been reported to negatively impact plant growth (reference below).

I want to do a study with Mimosa, how do I avoid the pseudoscience pitfalls?

1. It is important to plan ahead for adequate control of your project. Your sound-treated plants must be sonically and vibrationally isolated from the no-sound/vibration controls. However, the rest of the environmental conditions between the experimental and control groups of plants must be identical. It is important that both sets of plants are kept at the same temperature; the same duration, spectral distribution and photon flux density of light; the same level of soil moisture; the same level of soil mineral nutrients and pH; the same kinds of pests and the same level of pest-induced stress; the same levels of carbon dioxide and oxygen (among other gases) in the atmosphere; the same humidity; the same plant spacing; and, of course, identical genotypes and matching developmental stages among the plants being used.

   Most high-school (and university!) facilities lack duplicate facilities for such controlled studies, let alone sonically-isolated duplicate facilities. Schools are lucky to have even ONE plant growth facility with some environmental controls let alone two that are vibrationally isolated and otherwise synchronized.

   Moreover, working with simple frequencies and amplitudes of single sounds is complicated enough by harmonics and environmental reverberations. Music is a highly complex mix of tones, overtones, harmonics, rhythms, and polyphony on top of dynamic volumes. To think that you are dealing with one variable when one set of plants is treated with music vis a vis a control in silence...well, this is just not logical.. A project comparing acid-rock vs classical music is, to say it kindly, just over-the-top. Instead, you are going to need a sound generator that is capable of producing reliably-controlled sound. Such a device is not a common instrument in the high-school inventory.

2. You also need to be sure that you have replication built into your project. It is not sufficient to have only one plant receiving a treatment and one plant as an untreated control. You will need to have at least ten plants in each group...so you will need a total of twenty plants! These must all be the same species, the same genotype (or at least the same cultivar), and must be at the same stage of growth. Perhaps working with some freshly-rooted cuttings or some seedlings of the same age will help achieve these goals.

3. Finally, you will need to use some statistical analysis of your data. After recording the height of each of the plants in both the experimental and control groups, you will probably need to do a T-test or similar statistical procedure to compare the average heights obtained. Similar tests might compare fresh weight and dry weight of the individual shoots, etc. You cannot pool the shoots for a single weight, but must weigh each plant separately to allow for a statistical test! Moreover, the test needs to go through to completion! Your instructor should assist you with this.

If sound is so hard to work with, what do you suggest for a project?
My best advice for most students seeking a project is to try something with better prospects for success. The effect of different levels of light, temperature, fertilizer, water, pH, or salinity on plant growth would have a VASTLY higher chance for success. It is likely that your school does have one facility for growing plants and that you can manipulate one of these factors in a well-designed experiment. There is a high probability that a large-enough difference in any ONE of these factors between the treatment and control plants will reveal a measurable and statistically meaningful difference. There is much literature on each one of these real factors from which to glean ideas for your project manuscript. There are so many other good projects to do with plants, it is a shame that so many students are frustrating themselves with music projects.

Are there other project ideas I should avoid?
Other projects that frequently fall into the "pseudoscience" area include studies on plants responding to magnetic fields, the human voice, human emotions, or extra-sensory-perception.

I suspect that a good study might be doable with plants held in magnetic fields, but controlling and isolating magnetic fields is not a simple project. Dropping a magnet next to a plant is just not good enough! The field is NOT uniform (try the iron filings trick), so adjacent plants are not experiencing the same field strength or field direction, thus such replication is not really valid. Gauss meters are helpful in determining field strength but are not particularly easy to use or interpret in terms of direction. Also, secondary schools are unlikely to have a sensitive instrument. Moreover, magnetic fields will penetrate containers and include the areas nearby...where your control plants might be standing! So isolating the magnetic fields becomes difficult. Adjacent equipment and wiring all affect the field and generate fields of their own! The earth has its own magnetic field, so even your control plants are experiencing some magnetic field.

If you are an in-service teacher, PLEASE do not direct students toward class projects or science fair studies in pseudoscience. There is so much that is better for them to do. David R. Hershey has a good book entitled Plant Biology Science Projects, published by John Wiley & Sons Inc. in 1995. It contains much good advice on this topic...including an appendix on projects to avoid!

Conclusion
Perhaps music holds some human allure as a study variable, but many other environmental variables for plant growth have much better prospects for success!

Related Articles

Talos. 2001. If only corn had ears. ASPB News 28 (6): 8-9. This brief article collected some references about sound and plants. I show here the references given in that article with Talos' original annotations:

Braam, J. and R. W. Davis. 1990. Rain induced, wind-induced, and touch-induced expression of calmodulin and calmodulin-related genes in Arabidopsis. Cell 60: 357-367. [Talking Heads music at 60 db for 1 minute did not induce expression of touch-sensitive genes]

Daedalus. 1991. Green music. Nature 351: 104. [explains fancifully how music might be used as an herbicide, claims Charles Darwin played the bassoon for Mimosa pudica]

Davis, R. and P. Scott. 2000. Groovy plants; the influence of music on germinating seedlings and seedling growth. J. Exp. Bot. 51: 73. [sketchy abstract-only that concludes that music does make seedlings grow faster, but the response is quite species-specific]

Subramanian, S. et al. 1969. A study on the effect of music on the growth and yield of paddy. Madras Agr. J. 56: 510-516. (Paddy is indifferent to daily 30-minute exposures to recorded South Indian oboe music)

Weinberger, P. and M. Measures. 1979. Effects of the intensity of audible sound on the growth and development of Rideau winter wheat. Can. J. Bot. 57: 1036-1039. [a variety of sounds at 90 db had little effect, but plants subjected to 105-120 db showed reduced growth]

This page © Ross E. Koning 1994.

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