Title: Different Types of Drinking Water
Tia Sherman and Emily Kastl 3rd Hour

Abstract: We are doing this experiment to see what is the safest water to drink. This will help us to see what type of water is the cleanest and safest water to drink. We will take samples of all the water and grow bacteria from them to see which water has the least contaminants.

The purpose of this experiment is to compare different types of water, including, well water, city water, bottled water, and water from a water fountain. We plan to take tap water from multiple faucets, with some using well water and others using city, use a brand of bottled water, and samples from a water fountain to grow bacteria. “Water is an excellent solvent and can be sourced from almost anywhere on Earth. This property makes it prone to all kinds of contamination” ("The Water Purification Process”, 2012). Even with water purification systems, bacteria still constitute a real challenge to completely purifying it. “Drinking water, including bottled and tap water, may reasonably be expected to contain at least small amounts of some contaminants” ("Most Common Water Contaminants Index Page”, 2012). Our experiment is testing whether the bottled, tap, or water fountain water will contain the most amount of contaminants and bacteria. We will also compare the amounts of bacteria each water source contains in order to represent whether tap water or bottled water is truly cleanest for drinking. “Contaminants range from naturally-occurring minerals to man-made chemicals and by-products. While many contaminants are found at levels not enough to cause immediate discomforts or sicknesses, it is proven that even low-level exposure to many common contaminants will, over time, cause severe illness including liver damage, cancer, and other serious ailments” ("The Truth about Our Environment and Water”, 2012). To protect ourselves from the danger of contaminants, we want to see if it would be safer to drink tap, bottled, or water from a fountain to protect ourselves from illness. "But 40 percent of all bottled water in the U.S. is actually taken from municipal water sources" ("care2", 2012). Even though bottled water is purified, if our experiment shows that tap water is cleaner than bottled water then tap water should be considered being used more often so waste and the amount of plastic used will be reduced."The fact that on average bottled water cost $10 per gallon compared to tap water which costs $.0015 per gallon or about a tenth of a penny" (Education Database Online, 2012). Also, if tap water ends up being less contaminated, then people can start drinking more tap water and end up saving more money. The bottled water we would use is a common bottled water sold in the United States. "Common bottled water sold in the United States include Ice Mountain, Kroger, and Aquafina." (Best and Worst Bottled Water Brands, 2012). For the end result, we hope to find that tap water will produce less bacteria than bottled water; however, it is more likely that the bottled water will contain less amounts of bacteria due to a better purification process.

If we compare the amount of bacterial growth in well, city, bottled water, and water from a fountain, then the well water will consist of more contaminants.

1 bottle of Ice Mountain
Sample from a water fountain
Sample of Well Water (Tap Water)
Sample of City Water (Tap Water)
12 Petri Dishes
Sterile Cotton Swabs
0.5 cm^2 Grid Paper

1. Take 3 samples of the bottled water, 3 samples of water fountain water, 3 samples of well water, and 3 samples of city water in plastic cups.
2. Label the samples for each, the following way: use "a" to indicate city water, "b" to indicate well water, "c" to indicate Ice Mountain, and "d" to indicate water fountain water. Since there are 3 samples of well, city, water fountain, and bottled water, label the petri dishes 1-3 with the letter following the number that corresponds with the water source.
3. Prepare sterile petri dishes with nutrient agar.
4. Use a swab for each sample. Dip a sample's swab into that individual sample and do five strokes over the agar in the half of the petri dish. On the other half, leave it alone to serve as a control to determine how much bacteria ends up growing on its own. On the outside of the petri dish use a sharpie to draw a line dividing the two sides and leave the controlled side blank.
5. Repeat step four for each sample with a new sterile swab each time.
6. Label the petri dishes according to their samples, and seal each with tape.
7. Then, to take data, each day place the 0.5cm^2 piece of grid paper underneath the petri dish and count the approximate amount of bacteria in one square.
8. Repeat step 6 for 14 days and record the data. Average the amount of bacteria of the samples from each water source.


Throughout our experiment there was little bacteria that grew for any type of water so in saying that we can conclude that most waters are safe to drink. The water that produced the most amount of bacteria was the well water. As you can see in our graph, while the other waters stayed somewhat stagnant, the well water had started growing bacteria. This most likely happened because well water does not have as many tests to go through to make sure it is safe for the public to drink. The water out of the drinking fountain produced the most bacteria behind well water. The graph shows that there was not much bacteria that grew in the drinking fountain but there was some. This happened because the water probably picks up bacteria when it comes out of the spout of the drinking fountain. According to our data, city water and bottled water produced the least bacteria; therefore are the safest to drink. City and bottled water are the cleanest because of the multiple tests they go through before the public is able to drink them. Overall, our data tells us that well water contains the most bacteria. Now that we have done the experiment we can now choose the cleanest and safest water without any hesitation.

Our initial hypothesis "If we compare the amount of bacterial growth in well, city, bottled water, and water from a fountain, then the well water will consist of more contaminants" was proved right according to our data collected. Our hypothesis was supported because the well water produced the most contaminants and that is what our hypothesis predicted.

In our experiment there were are few places of error. Although our results clearly showed which water produced the most bacteria, some factors that could be improved on is having less bacteria from the air and surrounding area, the containers the water was in could have had bacteria in it, and lastly the agar may not have set properly or been contaminated before the water was on it. We can fix these things by prepping for the experiment in an environment with no bacteria, take the water directly out of the spout instead of transferring it, and finally we could make the agar in a bacteria free environment.

New Hypothesis:
If we compare the amount of bacterial growth in well water, city water, bottled water, and water from a fountain, then the well water will produce the most bacteria but the other types of water will produce bacteria as well.


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