Does the type of water you give a plant change how tall it grows? Each of these waters contains different dissolved substances. You can compare their effects on radish seeds.
Set up three covered boxes with rock wool plugs. Place two radish seeds in each plug. Fill each box with one type of water so the rock wool absorbs it from below. Add an air pump and keep all boxes the same distance from a light source.
Measure the height of each plant twice a week for three weeks. Weigh the plants at the end. In one trial, seltzer water produced the tallest plants and the most germinated seeds. Mineral water produced the heaviest plants. Tap water had the weakest growth overall.
Hypothesis
The hypothesis is that mineral water will be the best for the germination and growth of radish seeds.
For a comparison to mean anything, competing explanations have to be ruled out. All three boxes sit the same distance from the light source. Each holds rock wool plugs with two radish seeds, and an air pump supplies every box equally. The only deliberate difference is the water — tap, mineral, or seltzer. With light distance, growing medium, seed count, and aeration all held constant, the height and weight differences measured over three weeks point to the water type as the cause. Seltzer water produced the tallest plants; mineral water produced the heaviest; tap water showed the weakest growth overall.
Different water sources contain different dissolved substances, and those substances change how plants develop. Tap water, mineral water, and seltzer water each deliver a unique mix of minerals and dissolved gases to plant roots. In this experiment, seltzer water produced the tallest radish plants, while mineral water produced the heaviest, showing that what is dissolved in water shapes both height and mass.
Method & Materials
You will set up three boxes with different types of water, place two radish seeds in each box, and observe the growth of the plants over three weeks.
You will need black plastic boxes with covers, rock wool, mineral water, tap water, seltzer water, air pumps, a plastic cup, pH paper, garbage bags, a thermometer, and radish seeds.
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The results showed that the plants were tallest in seltzer water, and the average mass for plants was greatest for those in mineral water. The T-Test showed that the difference between mineral water and tap water was significant, as was the difference between tap and seltzer water, while mineral water to seltzer water was insignificant.
Why do this project?
This science project is interesting because it shows how different types of water can affect the growth of plants.
Also Consider
Experiment variations to consider include testing different types of plants, such as beans or carrots, or testing different types of water, such as distilled water or rainwater.
Full project details
Additional information and source material for this project are available below.
