Julia Balaeskoul Mrs. Kraus
November 15, 1998 Experimental Biology
The effects of tap water, mineral water, and seltzer water on the germination and growth of radish seeds.
How will tap water, mineral water, and seltzer water affect the germination and the growth of radish seeds? My hypothesis is that radish seeds will best germinate and grow in mineral water. Mineral water may have fewer contaminants that can hurt the germination of the seeds and perhaps this absence will help the growth of the plants. I also think that tap water will have a detrimental effect on both the germination and the growth of the plants. I am not sure what effect seltzer water will have on the radish seeds. It might be possible that the aeration will hasten growth (C02 makes water pH acidic.) On the other hand, this acidity level of the seltzer water might be detrimental.
Methods and Materials:
The materials used for conducting the experiment included the following: three black plastic boxes with covers having ten holes in them, rock wool, mineral water, tap water, seltzer water, air pumps, plastic cup, pH paper, garbage bags, thermometer, and finally some radish seeds.
First, the boxes were set up and each type of water was poured into an assigned box to the very top. Then two radish seeds were placed inside each portion of the rock wool. These portions were akeady stuck into the holes that had been made on the cover of the box. The proper cover was iaade by wrapping a black garbage bag wound the plastic cover and then making holes in the bag. After the seeds were careflally placed inside the rock wool, the cover was placed on top of the box, sothat the bottom of the rock wool was touching the water and, therefore, absorbed a necessary amount of water. The air pump was slipped inside the box through a specially made hole, so that the air would be able to get inside the box. All three boxes were away from the light source by a distance of twenty centimeters. Growth was observed in the following three weeks. The pH of the water was taken each time water was added to the box, which was every Tuesday and Thursday. The temperature of the room Was also observed and recorded daily. I recorded the changes in height of the plants a nool of six times, measuring from the stalk's base at the top of the rock wool to the tip of the plant. At the very end, I recorded the weight of the plants. Wherever two out of two seeds germinated, one weaker one was taken out on the last day of measurement and the height and the weight of that plant was recorded. If only one seed germinated, the height and the weight of the germinated plant were taken. if nothing germinated then that spot was considered unsuccesstbl and was discounted from the experiment. A week into the experiment, the boxes with mineral and seltzer waters were moved to a lower level, since the distance between the light and the plants had become less than twenty centimeters due to the increase in height of the plants. The same procedure was done to the plants that were in tap water, but in the third week of experimentation. Later, some pictures were taken and the data table of recordings was made and hung on the wall behind the table where the boxes were located.
The changes in height of plants were recorded six times, twice a week. Then data tables were created containing changes in height over the days. More seeds germinated in seltzer water than in mineral water or tap water (as shown in the Data Table D. The plants were tallest in seltzer water. The weakest ones and the fewest were in the tap water. The average height was greatest for plants in seltzer water (see Figure I). Finally, the tallest plants from each portion of rock wool, wherever the seeds germinated were weighed and the masses were recorded, together with the final height of the plants. The average mass for plants was greatest for those in mineral water, followed by those in seltzer water, and finally by those in tap water. (See Data Table II). 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. (See Data Table III). In seltzer water S out of 10 seeds germinated, while in mineral water 7 out of 10 did, and 6 out of 10 germinated in tap water. The average height of the plants on the last day of measurement was 6.9 cm in the seltzer water, while it was 5.7 cm in mineral water, and only 3.6 cm in tap water.
The seeds germinated and grew best in seltzer water. The average height of these plants was higher than those in mineral and tap water. However, it was not the plants from the seltzer water that weighed the most. The second most successfiil plants in terms of height germinated and grew in mineral water. While there were fewer of them and they were slightly shorter, their average weight was greater than that of those from seltzer water. Because in one instance (seltzer water) the height was greater and in another (mineral water) the weight was greater, it would be a mistake to say that one water is the better for both germination and growth of seeds. The plants that germinated in tap water did not do so well, and were the fewest in number of them with a low average mass. The seeds that were in mineral water started germinating faster and better initially, but were soon outstripped by those in seltzer water. The seeds that were in tap water were behind the other seeds in the development for most of the time, except during the first day when these few plants in tap water were taller than all the other plants, in both mineral and seltzer water. Tap water does cause some seeds to germinate and grow. However, it is not the ideal for the germination of seeds. Perhaps, fluoride has a negative effect on seeds and inhibits germination and growth. Perhaps other chemicals inhibit the germination of the radish seeds. Mineral water is less huinfizI than tap water. That could clearly be seen as many more seeds germinated and plants were both tdl& and heavier than those in tap water. The seltzer water had the most efficacious effect on the height of the radish seeds I was rather surprised to find this out. The bubbles in the gas water surely helped the seeds germinate faster; C02, which is what plants breathe and is the gas contained in seltzer, clearly promotes the growth of radish seeds. The reason the seeds in the seltzer water took a little bit longer to germinate in the beginning is because the roots weren't yet getting what would later be beneficial.
My hypothesis was wrong. I thought that the radish seeds would best germinate in mineral water, while they germinated best in seltzer water, and the worst in tap water. The plants that germinated and grew in the seltzer water were tallest and a greater number of seeds germinated in this gaseous water. However, the plants were heaviest in the mineral water. Plants in tap water germinated and grew the least. The seeds in seltzer water started out germinating and growing slower than the seeds in mineral water, and even those in tap water. The seeds in seltzer water maintained its superior growth rate in terms of length, but the seeds that were in mineral water got ahead mass wise The seeds that were in tap water started out as the tallest, but very soon were left in the dust. it is impossible to say for sure whether mineral water or seltzer water is better for the germination and growth of seeds. The T-Test only proves my point because the difference between the two is almost unnoticeable. However, even though the height of the plants in the mineral water was a little smaller, the roots were more abundant and therefore the weight of the plants was greaten We can't judge solely by height or by weight the success of the water used. We would have to observe the plants for a longer period of time to observe more drastic changes. This experiment provides is that tap water has a retardant affect on growth, particularly, in the earlier stages of development Further investigations might include determining the effects of seltzer water and mineral water on crops, on plants in other climates, and even the effect of seltzer water and mineral water on life forms such as animals and children.