Natural Science 1
December 11, 1998
Student Generated Lab Report
PLANT STIMULUS LAB REPORT
When our group first sat down to think of a project. We remembered a few experiments done in the past about stimulating plant growth through music and conversation. After brainstorming for a project that would be engaging, and would provide interesting results, we decided that plant stimulus would be a good choice. Our first idea was to only play music to the plants, but that quickly changed. Soon we had added touch, verbal, and musical stimulation. The verbal stimulation would include positive words of encouragement or simply speaking in a soft, easy manner. Another verbal form would include insulting the plant in a loud, derogatory manner and possibly screaming. The musical stimulation would consist of classical, heavy metal, reggae, R&B, Billy Joel, Country, New age, and Techno. After careful consideration we eliminated the harsh yelling from our experiment, for the reason that no one thought they could yell at a plant for an extended period of time. We also eliminated from the music category R&B, Billy Joel, Country, New age, and Techno because we couldn’t do all of the music categories, due to time constraints. Each of us felt that there wouldn’t be enough time for us all to do two or three different types of music for ten minutes on every test day. After many ideas had come and gone our group decided that we wanted to answer the question: Does outward stimulus, such as music, verbal or physical, have an effect on the growth rate of a plant?
Our purpose is to see how plants react to verbal, physical, and musical stimuli. We will be using classical, heavy metal, and reggae music, as well as speaking softly or sometimes reading from a book to, and gently stroking the plants’ leaves, stems, and blossoms. There will also be a control plant that will only receive natural stimuli such as water, sunlight, and air. We are hoping our results will show us a correlation between their growth and outside influences. The results of this experiment may lead to new ways of nurturing plants to grow to their fullest potential, or it may prove a popular theory, that music is very influential on plant growth, wrong. It is an interesting project because it’s results could show how plants respond to these different stimuli in similar ways, as do humans. We hypothesize that each of our different stimuli will affect the plant in many different ways. See graph below for the group members predictions:
Ali Tim Danielle Noah Lindsay Maggie
-’s= there will be a negative effect
’s= there is no effect ’s is what our group as a whole
rates the control plant
-’s= there will be a positive effect
This experiment has been done numerous times before, as it is a source of much interest and speculation. Randy Wayne, the noted author of Excitability in Plant Cells, explains how he has learned from his studies that plants respond electrically to physical stimulation (Wayne 140). Another article by Paul Simons refers to physical stimulation as well, showing that when either an insect or human touches a flower, they shorten their ring of stamen and release pollen. This experiment shows also that physical touch triggers electrical impulses, which drops the water pressure within the plant’s cells causing them to contract (Simons 14). Other studies have also shown that plants react to musical stimuli, such as Andy Cougnlan’s study which dealt with the composition of music to correlate with the amino acids in the plant, which in turn stimulates the growth of necessary proteins. According to Cougnlan, his affected plants grew to twice the size of the controls (Cougnlan 10). Peter H. Raven says that plants have evolved to respond to alterations in the environment. Some plants respond to electrical signals as well as touch, such as winding tendrils of the young Alaska pea plants, the collapse of the leaves of the sensitive plant Mimosa pudica, the triggered closing of the Venus flytrap, and the enfolding of the tentacles of the sundew (Raven 182). Furthermore, Paul Weatherwax wrote that Mimosa plants are one of many that respond to stimuli. The plant appears to be dead if it is disturbed, and it returns to normal size within minutes (Weatherwax). These experiments and past findings are what inspired our group to do this experiment. They also helped us to better understand the biological side of how plants react to outward stimulus.
In our pilot experiment, we grew several different types of plants in order to find the rate of growth, and which plant would be best for this experiment. The different plants consisted of carrots, waxed beans, radishes, raquettes, and sweet corn. We found that the waxed green beans would be most practical and beneficial to our needs. This plant would be suitable because our time restrictions only allowed for a fast growing plant. The bean plant, we found, would reach substantial measurable growth by the end of the semester, and our project.
The materials we used are: soil, water, clay pots, a plastic ruler, assorted CD’s and/or tapes in each of our allotted genres, and a boombox.
Our beginning steps are as follows:
5 seeds in each of the 6 pots
designated stimulation for the five plants
stimulation occurs 3 times a week (over a five week period)
Ten consecutive minutes every Monday, Wednesday, and Friday afternoon
one control plant gets no stimuli
After those steps were decided, and our plants started to grow, we proceeded with the rest of the experiment. The three measurements we took through out the period were of the height, girth, and leaves. First we measured the height with a flexible measuring tape in order to account for any bending or drooping. The girth was measured from the tip of one side of the plant to the tip of the other side. The numbers of leaves were also counted every week. All of our measurements were taken on Friday so that there would be a change in data from week to week. Tim was responsible for all of our measurements. We chose to have only one person taking the data so that each plant would be recorded equally. By providing equal treatment to our plants, we believed our statistics would be valid, accurate, and unbiased. The watering periods consisted of two cups of water for every plant and were administered on the days of stimulation (Monday, Wednesday and Friday).
The stimulation period consisted of the following. Each plant was taken into an empty and classroom to receive their treatment. The only outward stimulus that the plants received, were the ten minute sessions, and whatever verbal stimulation occurred in the greenhouse. When playing the recorded music, we made sure that each plants’ exposure to the stimuli was monitored and received an equal volume setting and time. The plants that were either spoken to or touched also received the stimulation for the full ten minutes.
For the designated “class participation day”, we split the class into three groups. Each group was taken into the greenhouse and showed how to take the measurements, and how we applied the stimulation. After learning how to record the data, each student was able to choose which stimulation they would like to observe. We did not want anyone else to administer the stimulation other than one our teammates for the reason that it could possibly change the stimulation, especially for the verbal and touching plants.
After November 29, when our final recording day was finished, we took all of our data and entered it into Microsoft Excel and Statview to determine what our results concluded and to find out if they were valid.
The most successful stimulation overall were the classical and verbal and verbal plants. The actual differences from plant to plant were not very large but these two plants rose above the rest in the majority of the categories. Our group feels that the reasons for the little variation from plant to plant might be due to not receiving enough stimulation. If playing the music, touching or talking to the plant were applied more often we felt there might have been more variation in the results.
For the average height per week all of the plants grew quickly the first six weeks except, for the reggae and verbal plants. From November twenty-first to the completion of the experiment, the classical and verbal plants rose rapidly to the top (See Average Height per Week Graph). On the final collecting day all of the plants were very close in height (between ten and twelve inches tall). After we found the results for the P-values of the height per week plants, we discovered that all the tests were insignificant except for the verbal and control, the touch and heavy, and the classical and control (see Paired t-test for height). The plants that were significantly different were the heavy metal and reggae plants. Their P-value was .0312, and the standard P-value for significant difference is .05 or below.
When measuring the girth of each plant we found that the classical plant rose steadily to the top of our graph until it reached about seven inches wide. After November 11, the verbal plant took the lead at seven and a half inches (see Average Girth per Week graph). On our final results we discovered that all of our plants were about seven inches wide with the touching plant at five and a half inches wide. When we compared the different plants to each other we found that about half of our results were significant while the other half not significant (See paired t-test for girth). Overall our plants were once again similar in the results, except for the touching and classical plants.
The final measurements we took were the average number of leaves per week. We found that the classical and verbal plants ended up with the most leaves, counting eleven. This was not always the case. The verbal started out rather low with the control plant but rose at the end. The reggae music in correspondence with its normal results scored lowest with nine leaves (see Average Number of Leaves per Week graph). The interesting part about this measurement was that none of the compared p-values were significantly different (see Paired t-test for number of leaves). Our stimulation appeared not to have an effect on the number of leaves on any of the plants tested.
When we first outlining the beginning of our project we came up with several questions. After tallying the results we were then able to answer them. The questions are as follows.
Which kind of music was most and least effective?
The type of music that was most effective was classical. In all of our tests, classical music proved to be helpful with the growth. The least effective type of music was reggae. To our group’s surprise, reggae music seemed to deter the plant growth. Our control plants had more growth than all of our reggae listening plants.
What effect did touch have on that specimen?
The plants that received physical stimulation did well in the beginning of our experiment but slowed its growth considerably during the last four weeks. The touching plants were just below the control plants on height the height measurements and significantly below the other plants on the girth measurements.
Was verbal stimulation helpful in the plant’s growth?
Verbal stimulation to the plants overall was helpful. These plants started off slow but caught up and barely surpassed the others, excluding classical, during the last four weeks.
What kind of things went wrong?
Throughout our experiment we had several problems. Due to Thanksgiving break and other vacations we had trouble staying on schedule according to our timeline. Another problem we had was finding someone to water our plants over thanksgiving break. Since the greenhouse was closed and all of us were out of town, we were unable to water our plants during this period. As our charts show, most of our plants had some difficulty over this holiday. We also observed little white bugs on our plants throughout the project. We are not sure if these bugs had an affect on our plants but they may be the cause of some holes that appeared on the leaves.
What was the most successful stimulation and could this be used to enhance plant growth?
The plants that received classical stimulation did the best, based on the measurements of height, width, and number of leaves. Once again, all of the plants were relatively close in these measurements, but overall the classical plants did the best. The plants to follow from second to fifth, are verbal, heavy metal, control, physical, and reggae.
Oct.14-Plant all test plants.
Oct.26-Begin music therapy
Oct.26-Nov.30-Music therapy three times a week (Mon, Wed, Fri,) As well as collect data every Friday. Also every Friday as a group, post progress reports.
Nov.30-Dec.7-draw conclusions, create final draft, and plan how to present to the class. Continue to post progress reports.
Dec.7-present to class or shortly there after.
Bandara, M.S. and Tanino, K.K. and Waterer, D.R. “Effects of Pots Size and Timing of Plant Growth Regulator Treatments on growth and Tuber Yield in Greenhouse-Grown Norland and Russet Burbank Potatoes. Journal of Plant Growth Regulation. 1998. 17: 75-79.
Bernal-Lugo, Irma and Leopold, A. Carl. “The Dynamics of Seed Mortality.” Journal of Experimental Botany. 1998. 4: 1455-1461.
Bonnet, Robert L., and Keen, Daniel G, Botony: 49 Science Fair Projects. Tab Books Inc. Blue Ridge Summit, PA 1989.
Couglan, Andy. “Good Vibrations Give Plants Excitations”. New Scientist. 1994. 1927:10.
Coulter, Merle Story of the Plant Kingdom. The University of Chicago Press. Chicago, IL 1959.
Klein, Richard M. and Deana J. Research Methods in Plant Science. The Natural History Press. Garden City, NY 1970.
Paul, Weatherwax. Plant Biology. W.B. Saunders Co. Philedelphia, PA 1942.
Raven, Peter H. Biology of Plants: Third Edition. Worth Publishers Inc. New York, NY 1981.
Simons, Paul. “Touching Flowers Work on Elastic”. New Science. 1993. 139:14.
Wayne, Randy. “Excitability in Plant Cells.” American Scientist. 1993. 81: 140-151.
We were unable to submit our last five pages. They included graphs and charts that displayed our measurements and t-tests.
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