If we use certain liquids, such as water or other pure substances, the growth rate and speed of plants will be affected positively, rather than using impure solutions, such as salt water, because the plant has less concentration of water to absorb.
 

If substances with higher concentrations of phosphorus are used to water the plant, said plant would grow exponentially faster in comparison to using other substances, because phosphorus is an important part of phosphate, which plays a significant role in forming DNA.

If nutrientful, mineral-rich substances such as bone meal that have an abundance of phosphorus, are used, then the rate at which the plant will grow will accelerate because phosphorus can be converted into phosphate which is a vital component in the maintenance and creation of DNA.

If substances with high amounts of nutrients and minerals are used to water a plant, as opposed to substances with high concentrations of sugar, then the plant’s rate of growth will accelerate because essential minerals such as phosphorus, potassium, & nitrogen play a direct role in the growth of plants; as opposed to high concentrations of sugar attracting harmful organisms and disrupting mineral balance.

Certain substances or liquids, such as Coca Cola or Fanta, hold high concentrations of sugar. While this may seem beneficial to a plant in the beginning, allowing the plant to have a steady source of food and energy, eventually unwanted or harmful organisms will be attracted to the plant. Another issue with using substances such as soda is that they contain almost no materials that are essential for a plant to flourish, thus disrupting the mineral balance within the plant. 

In the beginning, it may seem as though a plant is growing just fine, maybe even a bit faster than in comparison to just using water; however, it will soon halt its growth and essentially die within a few days.

On the other hand, if simply water were used, the plant would slowly but steadily pick up nutrients within the soil, allowing it to photosynthesise glucose at a steady rate. While the plant may appear to grow slower than if using substances with higher concentrations of sugar, it will far outlive the plant grown using high-sugar substances by a great margin.

Finally, using substances such as bone meal with higher amounts of phosphorus, calcium, potassium, nitrogen, and other essential nutrients and minerals to water a plant would allow it to not only far outlive the previously mentioned plants grown with their respective substances, but also allow the growth of the plant at a faster rate by an increased margin. 

This is because phosphorus, potassium, and nitrogen are essential nutrients for the growth of plants, and they play a direct role in the formation of DNA.

Variables: 

Manipulated: Liquid Used on The Plant

Responding: Rate of Plant Growth

Controlled: Species of Plant, Environment, Amount of Liquid, Amount of Sunlight, Size of The Pot, Type of Soil, Amount of Soil,

Procedure: 

1. Find a suitable environment in which there is an adequate amount of sunlight for your plant to inhabit
2. Get a pot and fill it 15cm deep with soil, ideally the same brand of soil for every plant
3. Plant the Garden Cress seed approximately  4-5mm deep in the soil. Ensure there is one plant for each liquid.
4. Place all pots in the same location.
5. At the same time each day, measure exactly 22 ml of each liquid and pour it steadily into each pot. Do all the plants as close to the same time as possible.
6. Later in the day, around sunset, measure and record the height of each plant. Make sure it’s done at the same time each day and all the plants are measured together.
7. After two weeks of watering and measuring, analyze the data you’ve collected.

As expected, the plants where water or diluted bone meal were used had no problems with germination or sprouting, and they managed to survive up until the end of the experiment. The plants watered with sodas such as Fanta or Coca-Cola, however, struggled with germinating and sprouted only for a short period of time before quickly dying out. 

The plant watered with a solution of salt and water managed to survive much longer than those with soda; however, I believe that the salt solution dehydrated the plant, as it quickly changed to a brownish-orange color and died out shortly after.

 - Water Started growing second and managed to survive all the way to the end of the experiment, it grew the second most amount, roughly 4.2cm

- Coke started growing after Fanta and managed to live longer than it, but it grew the least out of all the plants, reaching a max height of approximately 0.2cm

- Fanta, despite beginning growth before, and at a faster rate than, coke and salt water, ended up dying first, having a final height of around 0.5cm

- Liquid Bone Meal was the first to begin growth, survived through the entire experiment, and grew the tallest out fo all the plants, with an end height of about 5.1cm

- Salt water began growth on the same day as Coke, however it managed to survive much longer than both Coke and Fanta, reaching a max height of around 0.5cm, tying with Fanta

Substances with high concentrations of essential nutrients and minerals for plant-growth allowed the plant to exponentially flourish, whereas the substances with high concentrations of sugar and other harmful substances halted the growth and were detrimental to the plant. It was apparent the key to promoting quick and healthy plant growth was to provide a good balance between nutrients and minerals. Ensuring the plant wouldn’t dehydrate and wasn’t overloaded with external sugar also appeared to be important in the growth of plant life. However, our overall goal of finding a more cost effective way to germinate healthier and more nutritious plants failed because despite the fact that liquid bone meal allows for more rapid plant growth, it’s cost completely outweighs the benefits. All in all, there are technically better substances to use for agriculture, however nothing is more cost effective than water.

The real-world implications of our experiments and research is to test for the individual variables that allow for more effective liquids for germination and agriculture. Our intention was to hopefully discover a more efficient substance to grow plants with to help deal with the looming threat of a lack of food do the population boom currently going on and ease the fears held by people that they’ll starve because there’s not enough food to go around. Yet, although we didn’t find a more effective substance, people can still use the data we collected to isolate key factors involving plant germination and manufacture their own liquid that will be more effective.

Our sources of error mainly involve the measuring of both the plant height and the amount of liquid poured. Other than that there are only minor errors such as not having precise amounts of soil or the slight differentiation in the times in which they were watered.

References

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Hassani, N. (2023, August 26). Is Sugar Water Good for Plants? The Spruce. Retrieved February 20, 2024, from https://www.thespruce.com/using-sugar-water-for-plants-5221940

Impacts of salinity | Environment, land and water. (2013, October 1). Queensland Government. Retrieved February 20, 2024, from https://www.qld.gov.au/environment/land/management/soil/salinity/impacts

Plant nutrition for sustainable development and global health. (2010, April 29). NCBI. Retrieved February 20, 2024, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2887071/

The Role of Sugars in Plant Responses to Stress and Their Regulatory Function during Development. (2022, May 5). NCBI. Retrieved February 20, 2024, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9099517/

Water and Light, or, Can I Feed My Plant LaCroix? (n.d.). Tula House. Retrieved February 20, 2024, from https://tula.house/blogs/plant-reads/how-plants-work-or-can-i-feed-my-plant-lacroix