Introduction: (Initial Observation)
Some people talk to their plants. It’s a belief that plants feel the presence of human and grow better when people are around. There is a belief that Plants feel, perceive & read the human minds. Some people who keep plants around the house sing to them to help them grow. They say that if you say bad things to a plant, it will die.
It sounds silly, but according to some studies, these things are true. Scientists have proposed that plants can respond to certain stimuli, suggesting that they, too, are capable of feeling, and even experiencing pleasure and other emotions. (See more…)
I doubt that any of these are true, however there might be some truth in them. For example plant growth may be affected by sound. Sound waves create vibrations in the air molecules that eventually gets to every object around, including plants. Vibration may accelerate biochemical reactions of plant cells and increase the rate of reproduction. It is well known that stirring can accelerate chemical reactions and agitators are used in laboratories for this purpose. In bio chemistry labs vibrators are used to shake the flask containing nutrients and bacteria. Another possible effect of vibration of air molecules is higher rate of perspiration and loss of water through the plant leaves, causing the plant to suck more water and nutrients and grow faster.
In this project you will test to see if sound has any effect on the rate of plant growth.
Find out about plants and factors affecting plant growth. Read books, magazines or ask professionals who might know in order to learn about the properties and effects of sound waves. Keep track of where you got your information from.
Plant growth and development
Photosynthesis, respiration, and transpiration are the three major functions that drive plant growth and development. All three are essential to a plant’s survival. How well a plant is able to regulate these functions greatly affects its ability to compete and reproduce.
In 1973, a woman named Dorothy Retallack published a small book called The Sound of Music and Plants. Her book detailed experiments that she had been conducting at the Colorado Woman’s College in Denver using the school’s three Biotronic Control Chambers. Mrs. Retallack placed plants in each chamber and speakers through which she played sounds and particular styles of music. She watched the plants and recorded their progress daily. She was astounded at what she discovered.
Are your ferns drooping more than usual? Perhaps a bit of music may perk it up, for it is a known fact that music plays an important role in plant growth. But plants are choosy about the kind of music they want to hear.
Experiments show that plants thrive if soothing instrumental music is played in the background. On the other hand they shrivel and die if exposed to heavy metal or rock music. And now a Japanese company has created a gadget that puts you in touch with the ‘feelings’ of plants.
I want to do a study with Mimosa, how do I avoid the pseudoscience pitfalls?
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.
Music effects the human body in subtle, but powerful ways.
A well established fact is the human body and mind can be controlled and altered with music. Many scientific and medical studies have proved conclusively the tremendous effects of music upon the human physiology and anatomy. Music is used to lower blood pressure, treat mental illness, depression, mental retardation, insomnia and many others.
What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.
The purpose of this project is to see the effect of sound on on a certain plant species.
I said certain plant species because some plants may be more sensitive than others and we can not simply generalize the result of our experiments and assume that all plants will be affected the same way in presence of sound.
When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.
The independent variable (also known as manipulated variable ) for our research is the sound with two possible values (presence/ absence).
Dependent variable is plant growth in general, however we will also make daily observation and look for anything out of ordinary that may be contributed to the presence or absence of sound.
Controlled variables are air, temperature, soil, nutrients and light.
In other words you will make sure that all plant samples get the same amount of light, air and nutrients and the only variable will be the sound. So one group of plants get sound and the other group don’t get sound.
Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis. This is a sample hypothesis.
I think sound will stimulate plant growth. So plants exposed to sound waves must grow faster and stay healthier. Specially in an apartment or a greenhouse there is no wind to act as an stimulant, so the effect of sound must be more noticeable.
Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”
We will grow two identical groups of plants in identical environmental conditions, while one group is continuously exposed to sound of a radio and the other is not. After 3 weeks we will compare the rate of plant growth in both groups.
- Plant some seeds and wait for germination. You need to have at least 5 plants in each test group.
- Dispose of the seeds which do not germinate and transfer those who germinate to small flower pots it two groups
- Make two sound insulated boxes for plant growth. Light source for both boxes will be fluorescent light bulbs.
- Place on group of plants in one box with a transistor radio.
- Place the other group of plants in another box with no sound source.
- Make observations and water all plants daily.
- Measure and record the plant growth in
Following is a detail of the procedures:
Grow plants from seeds.
Why Grow from Seed?
The most obvious reason for growing plants from seed is the lower cost per plant. Another reason is that many varieties can only be started (or are easier to start) from seed. Finally when you start growing plants from seeds, you will be sure that all your plants are in the same age. It is also a good practice to hand pick seeds that are the same size. (Wash your hand before you start or use tweezers. Bacteria on your hand can grow on seed and void all your experiments)
Soaking the Seeds
Most seeds will benefit from being soaked in warm (even hot but never boiling) water. The addition of a small amount (1/2 teaspoon per pint of water) of saltpeter (sodium nitrate) to the water may help many varieties of seed with very hard seed coats. Soaking for a few hours up to as many as 48 hours in the case of seeds with very hard coats will speed up the germination process. After soaking, blot them a bit with paper towels and plant them in the growing medium immediately or before they have a chance to completely dry out again.
Containers for Germinating Seeds
Any kind of plastic container at least 3 to 3 1/2 inches deep will work. Used containers should be rinsed with a solution of about 1 part bleach to 9 or 10 parts water. Rinse and dry thoroughly before using. I have used the containers that supermarket delicatessens use for salads and pastries, etc. The only problem with them is that holes must be punched at the bottom for drainage. Then some kind of tray is needed below that to catch the overflow of water. The flats that are designed and manufactured specifically for germinating seeds seems to be the best solution over all. They are available with a variety of pocket inserts for various sizes of plants. It is possible to graduate from the smaller pocket inserts to larger ones as the plant begins to grow. They already have holes at the bottom that allow the excess water to drain into the tray in which they are snugly placed. The drainage of water is very important because soil that is too damp will either cause the seeds to rot or will allow the growth of mold, fungus and other diseases – one of the worst enemies of seeds trying to grow into seedlings. There are clear plastic lids that can be placed over these nursery flats to prevent drafts and to protect seeds from cold drafts. As the plants begin to grow these lids need to be set off center to allow air flow and finally removed completely to allow the young seedlings adequate air flow. These flats can be reused year after year as long as the 1 part bleach to 9 or 10 parts water solution is used to wash them and then allow them to dry just before reusing.
Growing Media, or Germinating Media is plural for Growing Medium or Germinating Medium, This is the material in which the seed is placed to germinate and grow. Of the various growing media, you will need to select the medium that is best for your specific purpose. Listed here are some of the options that are widely available for the gardener.
Peat moss is made up of decomposed aquatic plants and can be very acidic. It retains water and may not allow for adequate aeration or drainage. For this reason it is frequently used with other substances but not by itself.
Sphagnum moss is made up of dried bog material. It is fairly sterile and because it is very lightweight it can absorb as much as twenty times its weight in water. Its value as a fertilizer is not very good, and its ability to absorb water evenly is not very desirable. It, like Peat moss, is a good addition to make up a growing medium but is not the best substance to use by itself.
Vermiculite is expanded mica. It can retain a large volume of water for long periods of time. Although it contains a high level of magnesium and potassium and can hold nutrients and is good for aeration, It is not used by itself but is yet another ingredient in a final mixture for germinating seeds.
Perlite is a volcanic ash. It holds water on its surface but does not allow much absorption. It has no elements needed for plant growth and does not hold nutrients well. It does promote good aeration , stays cool and is a very good ingredient as part of a growing medium.
Sand is a good choice for root cuttings but is a bit too heavy for germinating seeds, it does not hold water, nor nutrients and is not recommended for germinating seeds.
Rich garden soil is good for plants but it does not offer the conditions necessary for germinating seeds because it does not allow for proper aeration and drainage for seeds. It is not sterile but after sterilization (bake it in a pan at 180 degrees for 30 minutes) it can be used as an ingredient in a good growing medium.
Special mixtures prepared for germinating seeds are available at nurseries and garden centers. These are very good for starting your seeds. For a little less money you can prepare your own mixture. Mix 1/3 to 1/2 sphagnum or peat moss or any combination of both with 1/2 to 2/3 vermiculite or perlite or any combination of both will make a very good growing medium for germinating most any kind of seed. The ideal mixture would have about 50% solid material, 25% air space (oxygen) and 25% moisture.
It is generally more economical to germinate seeds during the warm months when the heat and light from the sun is free. Temperatures generally in the mid 70s up to 80 degrees f. are needed to germinate most seeds. Although there are seeds that require 70 degrees and lower. When temperatures inside drop below 70 degrees at night the germination of many kinds of seeds can be impeded or even halted. It is important to keep the seeds at a constant temperature and away from drafts such as too close to doors and windows. If they are growing near a window to take advantage of the light during the day, it is a good idea to move them farther back as the sun sets to avoid exposing them to drafts. The lack of constant heat is one of the main reasons that seeds fail to germinate.
When germinating seeds indoors during the winter or indoors in air conditioned environments it is important to keep the soil warm. There are several ways to accomplish this. In greenhouses heating coils can be used. For smaller batches of seeds in the typical home it is possible to set the seed flat upon blocks and put a 40 watt light bulb underneath the flat. 60 to 100 watts are likely to generate too much heat. The soil should feel warm, but not too warm. Care should be taken to avoid contact with flammable substances. A heating pad placed beneath the flat or seed containers can be used but care is needed for this too since the controls on some of these heating pads will allow too much heat. Again the soil should feel comfortably warm not too warm or hot.
Besides warm soil, the air in the room where most kinds of seeds are germinating will need to be at least in the 70s. The higher up you place the seed flats the warmer the air is likely to be in any room. Since heat rises, the top of a refrigerator would be warmer than on a table at waist level. If the room temperature is 70 or 72 degrees f. the difference of 2 or 3 feet of height where the same room may have temperatures from 74 to 78 degrees f. can make the difference in whether or not some kinds of seeds will germinate. Those that require lower temperatures should be placed at lower levels within the room.
Once the seedlings appear and begin growing into plants, the heat should be reduced to around 65 to 70 degrees f. during the day with temperature as low as 55 to 65 degrees f. at night. There are exceptions to this. Melons, cucumbers, eggplant, peppers, tomatoes, and nearly all tropicals will prefer 70 to 80 degrees f. during the day and 60 to 70 degrees f. during the night.
Light is not the same thing as heat. Although heat is generated by a light source such as the sun or artificial light, it does not continue generating heat when the lights are turned off or when the sun sets. The heat required to begin the germination process should remain constant, day and night, at least during the early stages. The light source may or may not remain constant, but will be necessary for long periods. Simulating the longer daylight hours of spring – 10 to 12 hours per day is best for most species. Those seeds that require constant light will need artificial light (fluorescent or grow lights are best) until germination occurs and possibly for some period of time afterwards. Seeds that require total darkness should be covered with black plastic until germination occurs. Once germination has occurred, all seedlings will need enough light for photosynthesis to enable them to develop into strong healthy plants. If seedlings are growing in overcast conditions of winter the continued use of artificial lights will be required.
Before sowing seeds in the growing/germinating medium water it thoroughly and let it drain off. Sow seeds and cover with plastic, glass, or with the specially designed clear plastic covers that can be purchased with the nursery flats. These seeds will probably not need to have anymore water nor mist added until after germination occurs but it is still a good idea to check the top of the growing medium daily to be sure. Too much water (inadequate drainage) will cause seed rot, mold, or fungus. Check the growing medium every morning. When the top layer feels a bit dry it can be misted. Watering from the usual containers can disturb the seeds. It is best to sprinkle lightly or better yet, use a spray bottle with a mist attachment. This fine spray will lay down a nice amount of moisture and will not cause gullies or pockets to disturb the seeds. Water is best at room temperature or even a bit warmer – never use hot water nor water that is too cold such as cold water right from the tap. The best time to water is in the morning. Do not allow the growing medium to dry out and do not water so much that is remains soggy or wet. Always water from the top (a mister is best) rather than rely on adequate moisture to soak up from the bottom of the tray. The growing medium needs to be watered from the top down to assure an even distribution of moisture throughout. too much moisture remaining at the bottom of the tray will cause problems associated with inadequate drainage and the layer at the top may remain too dry.
The first growth to appear on the seedlings are the cotyledons. These are not true leaves but are food storage cells. This food will only last the seedling a short time and it will be necessary to begin feeding the young plants just as soon as the first true leaves begin to appear, usually within a couple of weeks. Purchase a good quality all purpose water soluble plant food such as Miracle-Gro. Always read the label. When fertilizing young seedlings, start out with a mixture that is about 1/4 the strength that is recommended for mature plants. Use this solution about once a week. Gradually increase the ratio as the plant grows and becomes stronger. After several weeks and the plant seems strong and healthy increase the mixture of plant food to water to the full strength as recommended on the label. Do not believe, in the case of plant food or fertilizer, that “more is better”. The manufacturers test their products and know what formulae is best. Follow the instructions on the label.
What type of seeds and how many?
You can plant any type of seed that you like. Just consult the seller and make sure that they will germinate fast. If you are not sure, just use beans (any type you like) as seed. Plant 3 seeds in each pot. The reason that you plant 3 in each pot is that some seeds may fail to germinate. You will need at least one germinated seed in each pot. Simply use a pencil to make a 1″ deep hole, place a bean seed in the hole and cover it.
Another method for growing beans is keeping the seeds out of soil or medium until they germinate.
First start the seeds off into growth by chitting them. Chitting overcomes the problem of seeds rotting before they germinate. Chitting, shown in steps 1 to 6 below, is carried out using a plastic food container like those used for sandwiches or the freezer.
Lay a water retentive liner such as a folded paper kitchen towel in the base of the box. Spray the paper towel evenly with water to ensure that it is thoroughly moist all over. Pour away any excess water. Place the bean seeds evenly over the damp towel, about an inch or so apart, to allow for as little root disturbance as possible when the roots grow.
Put the lid on the box. Label the box, most important if your are growing different varieties or other types of seed as well. Place the box in a warm place such as the airing cupboard or sunny window ledge.
After the first week inspect the seed boxes carefully each day to check on germination. After the seeds have germinated and their roots are an inch long they can be planted into pots. Fill a 3 and a half inch pot with Potting Compost. Make a generous sized hole in the center of the pot so that the seed can be just laid into it with the root pointing down, but without dibbing the root down into the compost and bruising it in anyway. Fill the surrounding area of the hole with compost to within half an inch from the top of the pot to leave room for watering.
Water the pots to ensure the compost is moist but not saturated. Then place the pots in two different sound proof box that you make in the next step.
Check regularly that the pots are not showing signs of drying out, watering when necessary.
Testing the effect of sound
You need two sound proof boxes for this experiment. Two glass aquarium can be used for this purpose. Glass is relatively sound proof and gives you the choice of using natural light or synthetic light.
The light source also can be fluorescent Strip-Lite fixtures used on aquariums.
IMPORTANT: Only use Strip-Lites over glass tops. They are NOT designed to be safely used over open water.
If you don’t have access to two empty glass aquariums, you may make your own sound proof boxes in many other ways.
For example you may alter carton boxes and make them sound proof for this purpose.
You will need two sound proof boxes. You can make a sound proof box by getting a 2′ x 2′ x 2′ carton box and cover inside and outside of the box with some sound proof material. Material used for drop sealing are good for this purpose and you can buy them from hardware stores. Any rubber based foam also is good for sound proofing the boxes. Music suppliers and those who sell material for constructing a music studio carry sound proof foam tiles. Carpet and blanket works as well. Top side of the box can remain open for light to enter, however you will close that too after placing your light source. Your light source can be a fluorescent light.
Both boxes must be sound proof. In one box you place a small transistor radio. Since the box is sound proof, you can rise the volume and not much sound will leak out. The other box also is sound proof so the environmental sound or the sound leaking from the first box will not get to the other group of plants.
Place half of your plant samples (5 plants for example) in the sound proof box with a radio. Place the light and secure it at the top of the box. Cover the box so no sound will leak. (You can ignore small sound leak). Call this sound box.
Place the other half of your plants in another sound proof box, place and secure the light at the top of the box. Cover the box so outside sound will not enter the box. Call it the silent box.
Open the boxes every day and water the plants with a measuring cup or graduated cylinder. Make sure all cups get the same amount of water and nutrients. Make daily observations and record your results and then close the boxes.
After 3 weeks make your final observations. Since you started from seedlings and young plants, any possible effect of sound must be noticeable at this time.
I have not done this experiment myself. Please let me know about your results.
Make a data table:
Now that you have two groups of plants, one grown with sound and the other grown without sound. Measure the height of all plants in each group at the end of your experiment and record them in a table like this:
|Plant #||Sound Group||Silence Group|
At the end calculate the average plant height in each group and write them in the last row of your table.
Make a graph:
You may use a bar graph to visually present plant growth in different sound conditions. Make two vertical bars. Label one of them “Sound Group” and label the other one “Silence group”. The height of each bar will show the average plant height in that group.
Materials and Equipment:
List of material can be extracted from the experiment section.
Results of Experiment (Observation):
Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.
No calculation is required for this project.
Summary of Results:
Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.
It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.
Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.
Related Questions & Answers:
What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.
If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.
If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.