Experiment conducted by Sarah Engle and Alexandra Bicki, report by Sarah Engle
Introduction:
(A) Overview Of The Experiment
Our test is about
determining which tap water is better in Gordon, and if there
actually is any difference between the three bubblers in Middle
School, Lower School, and Early Childhood. We want to know if
the middle schoolers have better water in their bubbler than the
other sections. To prove which water was the 'best' we tested
pH, alkalinity, copper and iron of the water. We repeated the
procedure three times for each sample water and found the average.
The reason we wanted to test both bottled and tap water was to
determine if there was a large discrepancy between bottled water
and the average reading of the Gordon bubblers.
The reason we tested pH was because we wanted to find out if the
water was acidic or basic. A pH reading of 7.0 is neutral; 6.9
and below is acidic, and 7.1 and greater is a basic (the pH scale
is 0.0 to 14.0). A lower pH doesn't mean the water is 'worse'
because it is more acidic. In fact, even though basic water is
more alkaline a pH reading of greater than 8.5 could mean that
the water is hard. Hardwater is not a risk to your health, but
can cause other types of pesky problems. It can cause an alkali
taste to water, and cause a formation of deposit on sinks and
laundry basins (which could be similar to the material of the
bubbler in the Early Childhood.) It also decreases efficiency
of electric water heaters. (htttp://wilkes.edu/~eqc/ph.htm)
The reason we tested alkalinity was because we wanted to verify
our pH readings and check how alkaline the water was. The higher
reading the more alkaline a substance is.
The reason we tested the copper of the water is because copper
is an important factor to your daily diet as well as a health
risk. It is recommended that each adult consume 1-2 mg of copper
a day, and each child consume .5-1 mg. Exposure to too much copper
can be harmful. Over a logn term if you drink water that contains
higher than the normal level of copper the results could be diarrhea,
stomach cramps, vomiting, and nausea. High intakes of copper (intentional
intakes, for example pills) can cause liver and kidney damage,
and even death. We wanted to know if the readings of copper were
so high that they could affect the health of the students at Gordon
considering on average each student drinks from a Gordon bubbler
at least once a day. (http://www.aaamagnetic.com/pages/copper_health.htm)
We tested the iron of the water to explore the same reasons listed
above for copper. We wanted to see what the levels of iron were
because, although a normal 14-18 year old is suggested to intake
13 mg of iron a day, iron has a high potential for toxicity.
(B) Question And Hypothesis
My question was which
water is better bottled or tap, and which Gordon bubbler is better.
My hypothesis was that bottled water would have (as an average)
greater levels of alkalinity, and around neutral (7.0) levels
of pH because I believe they go through purification processes
while Gordon water is filtered through our pipes.
I also predicted that there would be no difference in the readings
between the Lower School and Middle School bubbler that we tested
because they are the same make, and they also are newer bubblers.
The bubbler in the early childhood is an earlier make and I predicted
that the readings of copper and iron would be higher, but not
by much, because I believe our water is filtered enough so that
there aren't high levels of copper and iron.
(We also tested vingear and distilled water because we knew vinegar was very acidic and wanted to put the waters on a scale, and we tested distilled water to make sure our instruments were calibrated. They are a means of comparison, not a part of our experiment.)
Data
Analysis:
(A) Data Table
This table shows the data from all of my tests. For each test I tested each sample water three times and found the average of the three. Conducting the test three times and finding the average makes your reading more accurate than if you just tested it once. In bold are the averages (mean) and the ranges for each test.
(B) Graphs
Alkalinity Graphs
This graph shows the alkalinity readings of each of the bubblers. The EC bubbler has a reading of 36, while the LS and MS bubblers have a lower, more acidic, reading of 29 ppm. The intervals on this graph are not accurate because they should be 4 which are the intevals on the alkalinity titrator
This graph shows the average of all three Gordon bubblers, compared to the average of all five bottled water averages. The bottled water average is 71, and is more alkaline than the more acidic Gordon bubbler average of 33. The intervals on this graph are not accurate because they should be 4 which are the intevals on the alkalinity titrator.
This graph shows all of the sample substance's alkalinity levels. Evian has the most alkaline reading of 221. The closest Gordon bubbler reading to that is 36, for the Early Childhood. The intervals on this graph are not accurate because they should be 4 which are the intevals on the alkalinity titrator
pH Graphs
This graph is a pH scale. It places the readings of the sample waters on the pH scale from 0.0 to 14.0 (0 to 6.9 being acidic, 7 being neutral, and 7.1 to 14 being basic.) The light blue dots signify the bottled waters, and the dark blue marks signify the bubblers. The bottled water readings are clumped around 7-7.4 area (which is neutral) while the bubbler readings are settled around the 9.6-9.7 area.
This graph shows the different pH readings of all the sample water as above, yet it is shown in a bar graph. You can see that
This graph shows the pH of the MS, LS, and EC bubblers. The MS bubbler has the highest pH reading of 9.7, and the LS and EC bubbler have a pH reading of 9.6. Yet, since the margin of error for pH is +/-.1, readings which have a .1 difference from another reading are considered the same. This means each bubbler technically has the same pH reading. Since the average reading is 9.6, this means that the water could be hardwater since it is greater than 8.5 pH units.
Iron Graphs
This graph shows the iron levels of all three bubblers. They all are .02, which is relatively low on the iron scale.
Conclusion:
(color of strips, range of poland spring + aquafina, alkalinity subjective ness) My question was which water is better, bottled or Gordon tap (for alkalinity and pH tests), and which Gordon bubbler was better. My hypothesis is that bottled water would have more neutral readings for pH because they are filtered and purified so they are more basic/neutral, and that the Early Childhood bubbler would have higher readings of pH, iron and copper and lower alkalinity readings (thus making it more acidic than the other two bubblers) because it is a different make and it is in an older building, and I inferred the pipes were older.
(A) Alkalinity
Since there were many aspects to my hypothesis and question I decided to address them seperately. I predicted that the alkalinity reading of bottled water would be greater than Gordon tap because it had gone through more purification. The average reading of all three bubblers for alkalinity was 31, and the average reading for all five botled waters was 72, that is almost two times the tap water average. Although the average proves my hypothesis correct, I believe it is also because of the different bottled water brands I used. For example, the readings of bottled water ranged from 221 ppm (Evian) to 10 ppm (Aquafina.) Poland Spring's reading was 35, Dasani's was 16, and Evian's was 73. I do not think that the 71 average is a true representation considering the readings were really spread out. Yet, the bubbler readings were within 7 ppm of eachother (within 3 noting the +/-4 ppm margin of error). The MS bubbler had a reading of 29 ppm, as did the LS, and the EC had a reading of 36 ppm. Som the 31 ppm average is a fair representation of this data. To conclude I believe that it really depends which bottled water you use. Some are better than the Gordon tap, and some aren't.
The second part of my hypothesis which related to alkalinity was that I hypothesized that there would be no difference in the readings between the Lower School and Middle School bubbler that we tested because they are the same make, and they also are newer bubblers. The bubbler in the early childhood is an earlier make and I predicted that the alkalinity reading would be lower (more acidic) because the pipes are older. This part of the hypothesis was proved incorrect, in fact, it was proved just the opposite! The alkalinity reading of the EC bubbler was 36, while the readings of the LS and MS bubbler were both 29. Although my hypothesis was correct that LS and MS would have the same reading because they are the same make, and in newer buildings, the alkalinity reading of the EC bubbler was greater than the other two. I think this is because of the way I conducted our alkalinity experiment. In section D of the procedure, step 6, it says to stop adding the alkalinity titration reagent when the solution turned pink, except for each time we kept adding solution until it turned completey pink. Yet, there were times when the solution turned from blue-green to orange-y pink, and we didn't use that reading. I think these results were caused by the innacuracy of our procedure. Yet, I am not competely positive, so I want to research more on alkalinity of the three bubblers, and test them over a period of time, first thing in the morning before anyone uses them, and set a color standard so we can get an accurate reading for 'pink.'
One thing I was confused about testing alkalinity was that the reading of distilled water was 8, which is acidic. Yet, you'd think that distilled water would be more basic. I think that as the minerals in the water increase, the alkalinity increases also, because distilled water has no added minerals, but Evian, with an alkalinity reading of 221, has many.
(B) pH
The part of my hypothesis which addresses pH predicts that bottled water would have more neutral readings for pH because they are filtered and purified so they are more basic/neutral. This aspect of my hypothesis was proved correct. The average pH reading of all five bottled waters was 6.9. Four of the five bottled waters range from 7.0 to 7.4, and Dasani, with a reading of 5.7, is the only bottled water with a reading below 7.0, so I believe this average is an accurate representation of the data. The bubbler average was 9.6 (two of the readings were 9.6, and one was 9.7). Since the average pH of Gordon bubbler is greater than 8.5, this means that the water is hard, and can pose a threat to the bubblers themself by wearing them away over time. The data shows there was no difference in the pH readings of the three bubblers. The MS and LS bubblers each had a reading of 9.6, and the EC bubbler had a reading of 9.7. Since the margin of error is +/- .1, 9.6 is considering the same as 9.7, so there is no difference in pH. I believe this is because there isn't a great enough difference in the pipes. In fact, I haven't researched the piping material of the different buildings, and they could be the same. Or, pipes could not have any correlation with the pH levels of the water.
(C) Iron
I hypothesized the EC bubbler would have higher iron readings than the other two bubblers because of when the bubbler was built. The data shows otherwise. The iron readings for all three bubblers were .02 mg/l, which is a relatively small amount of iron. I believe the reason there is no difference between the bubblers is because even though the bubblers were put in at different times, it did not have a significent enough impact on the iron levels. Also, I believe to make accurate concluding statements I first have to find out how the pipes connect to the different bubblers, and if infact they have different pipes.
We encountered one problem with this experiment. This was the subjectiveness of the test strips. Some of the colors were so close you could not tell whether it had a reading of .02 or .03 mg/l. I think using an instrument like a pH pen (and making sure it is calibrated) would be much more accurate.
It is good the levels of iron in the water at Gordon are low so they do not pose any health risks of overexposure to the Gordon students.
(D) Copper
I hypothesized the EC bubbler would have higher copper readings than the other two bubblers because of when the bubbler was built. Each bubbler had a copper reading of 0.0, which means it had no copper at all (or that our instruments could detect), so my hypothesis was proved incorrect. Yet, if we used different instruments we might be able to get more accurate readings because you compared the color of the test strip to a color chart, and the colors were very close to eachother, so it was hard to decided which reading was which. If I was to do this experiment over, I would use a more specific instrument if any, but my hypothesis would stay the same. The good thing is we know the levels of copper in Gordon water is extremely low so it doesn't pose a health risk for students!
Bibliography:
For the font Rose Water
http://www.copperinfo.com/health
http://www.aaamagnetic.com/pages/copper_health.htm
http://wilkes.edu/~eqc/ph.htm
For the information about copper, pH and iron
Report and Graphics
© 
2003
Mrs. Fisher's 8th Grade Science Class
Monday, April 28, 2003
A Tribute To America
- I Support Our Troops
