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Science Fair Experimentation

This post is an analysis of my science fair topic this year.

"The Effect of Carbonated Water on Plant Growth"


Procedure


In setting up the experiment, I scattered approximately 20-30 Garden Cress (Lepidium Sativum) seeds across an evenly spaced, plastic pot filled with 1.5 inches of sandy loam cacti soil. I repeated this process for each of my three experimental groups (and each group would be repeated 3 times, for a total of 9 pots planted, Figure 1). Plants were grown under a LED growing light [PYLYFE: Amazon Shipping] set on an automatic light/dark timer (12 hrs on, 12 hrs off -> on at 7am and off at 7pm). I repeatedly watered the cress with their designated water every other day and measured average plant growth in cms to calculate the results. The experiment was conducted for 4 weeks. Group 1 took 2 weeks, and Groups 3 and 4 grew together in a separate 2 week period.


Materials


1. Measuring cup (Pyrex: Medium Sized Pitcher)

2. pH Testing Strips (Litmus Test Strips 240: LabAider Store & Atlas Science)

3. Soil/Fertilizer (Wonder Soil: Organic Cactus and Succulent Soil - 12 Quart)

4. Seeds (Hemani 100% Pure Garden Cress Seeds - Lepidium sativum)


5. pH altering kit (LabAider Store & Atlas Science: pH Up and Down)

6. Pots for growing (June Fox Square Nursery Pots 3.3 Inches Flexible Plastic Seedling Pots Square Pots for Plants, Succulent, Flower)

7. Growing light (PYLYFE: Indoor Red Blue LED)

8. Ruler (STAPLES)


9. Sparkling Water (Crystal Geyser - Sparkling Spring Water)



Question / Problem


In this experiment, I am exposing various groups of garden cress to different types of water to test their rates of growth. Therefore, my question is “How does carbonated water affect plant growth?”


Hypothesis


I believe that the groups of cress exposed to carbonated water will grow more abundantly because an increase in the exposure to carbon dioxide will improve the photosynthetic process, which gives more energy to the plant and increases growth.


Purpose


I am conducting this experiment because I have a garden out back where I enjoy growing smaller vegetables and tweaking certain factors to get them to grow better. Months ago, I read an article about a group of scientists watering plants with Club Soda from the University of Colorado, so I wondered whether regular carbonated water would do the same thing. Therefore, my only purpose here is to find out whether there were any separate outcomes to this format of experimentation.


Research / Background


Various experiments were conducted in the past to test the validity of whether carbonation will actually help plants grow. Many studies have shown that plants do have the ability to absorb carbon via root systems, and others have also shown that plants will pertain increased levels of calcium, magnesium, and zinc in their leaves. Quoting a study from the University of Colorado in 2002, “Plants watered with carbonated water grew more than twice as fast and developed healthier shades of green over a 10 day period. That study was performed using Baby Tears (Soleirolia soleirolii). However other studies have found carbonated water did not change the growth rate, or in some cases, stunted growth.” The outliers in this experiment were likely due to the acidity of the water interfering with the nutrient absorption process as the ph of the soil can have great effect on nutrient intake. There’s a distinct possibility in experimentation that soil pH might drop too low (5.5) and will start to toxify aluminium and magnesium in the soil, therefore stunting growth. I hope to contribute to the field of agriculture in this experiment as carbonated water might prove to be a more affordable alternative to fertilizer to improving plant growth.


Data


Below this sheet you will observe two images of Experimental Batch #1, one image depicts the sprouts of the plants on Day 2, whilst the other depicts them fully grown somewhere during Day 12. Two other charts are also labeled clearly as they present different variables of this experiment. One presents the percentage of growth the plants undergo with different water types, whilst the other presents how the plants reacted to both pHed and carbonated water. This allows me to interpret whether it was the carbonation or the pH that interfered with the plant’s growth. A general list of all results is also posted below.


Results


Unfortunately, my hypothesis proved incorrect as the plant groups watered with carbonated water grew less in proportion to the tap water group. Proportionally, cress watered with carbonated water grew anywhere from 4-7% less than the average group of cress watered with tap water. However, the pHed tap water group actually grew less than the the group of plants watered with carbonated water, anywhere from 6-8% less until we neared the end of the experiment. These curious results will be elaborated upon in my conclusion.


Conclusion


In this experiment, I have found that tap water works best in plant growth, but the data is rather inconclusive. Throughout the experiment, I have observed that cress watered with tap water grows better than the groups watered with both pHed and carbonated water by either small or noticeable degrees, as pointed out by the statistics in “Results.” However, I have a theory on why pHed tap water grew less than carbonated water’s plant group. My theory is that the carbonated water and the pHed water both dropped the soil pH low enough for minerals to toxify and decrease growth, as presented in “Research / Background.” This is possible as I had neglected to notice that the natural oil pH of Sandy Loam Cacti Soil, was already relatively low (5-6), which allowed the pH imbalance from the water to toxify and decrease nutrient saturation. Lastly, the beneficial effects of the carbonated water allowed the plant to thrive more than the pHed water groups as it had only brought adverse effects to the plants with absolutely no benefit. Therefore, since the group watered with tap water was subject to no adverse effects placed upon it with a ph change, or perhaps benifited from a pH boost from the natural pH of tap water, it grew more abundantly than all the rest.


Next Steps


My theory presented in “Conclusion” has the potential to lead another experiment that I could elaborate on as I can test whether it’s the quality of the soil that would reduce the effects of carbonation on plant growth.


Images & Charts:


*An image of what the experiment looks like.


*A graph of their growth in terms of percentage.

*A comparison of plant growth when you change the pH factor.



*A chart that displays their growth throughout the course of the experiment.


*A batch of Cress on their 2nd day of growth.




Reference Cites









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