Unit 1 Foul Water Activity
Julia Tolmachyov, Francesca Cali, Galen O’Neill
1) Introduction Throughout this lab, the ultimate goal was to completely filter and purify all organic matter, dirt, bacteria, and harmful substances in the water available to us in order to survive on the desert island. Undoubtedly, there were many substances in this water that could be harmful to the body. Most likely, the water was filled with dirt, dead organisms, bacteria, algae, etc. Oil and solid materials were also detected in the water. Again, our goal is to remove said impurities. Based on our hypothesis, we planned to purify the water with a method using all available resources. This included filter papers, gravel, sand, charcoal, and fire. We planned to filter the water’s large particles through the gravel and sand, the filter paper will separate these into the smallest possible particles. We plan on adding charcoal to the filtered water to make it clearer. This remaining sample will be boiled to kill all harmful bacteria.
Hypothesis: The foul water can be purified by pouring the water through filter papers and a Styrofoam cup filled with sand and gravel, and the end result will be boiled to remove all solids and impurities
2) Procedure/Data/Observations For the first trial of this experiment, it was decided to first drain a sample of the contaminated water to remove any visible sediment. First, the Styrofoam cup was taken and its contents--gravel and sand--were transferred into a small beaker to hold. Three holes were punched in the bottom of the cup, which was used to drain the water. Next, a piece of filter paper was placed at the bottom of the cup so that all liquids filtering through the Styrofoam would eventually come in contact with and go through the bottom filter paper. Since there was unlimited gravel and sand, the cup was filled about ¼ of the way up with gravel rocks, and ¼ up with sand, in order to help drain and filter the foul water. Because there was only a limited amount of charcoal, this resource was not being used until it was certain that this filtration method was successful. An iron ring attached to a ring stand was used to hold a glass funnel in place over the Styrofoam cup, which itself was nestled in a beaker in order to catch the filtered water. Another filter paper was placed in the glass funnel. 50 millilitres of the foul water was poured into this glass funnel through the filter paper. The water took a very long time to drain completely, so it was left to drain throughout the day. On day two of lab, several new methods to purify the water were tried and observed. At 8:00 a.m., it was found that the trial from day one--the Styrofoam cup filter--helped remove all solids from the solution, but it did not separate the water from the oil present in the mixture. This was a problem because not only was the water still not safe to drink, if one attempted to boil this substance, it would combust, thus ruining the trial and wasting important resources. The first trial of day two attempted to separate the water and the unwanted oil in the filtered sample. Since oil floats above water in this heterogeneous mixture, the solution was slowly poured out of the beaker in an attempt to separate the oil and water. If this mixture had been homogeneous, the water and oil would not have been distinguishable in the mixture. This trial was unsuccessful because no matter what angle or position the solution was poured, the oil remained on the top, as oil has a density less than water and will always float on the surface. Even though this trial was unsuccessful, no resources were wasted or lost. In the third trial, 110 millilitres of a new sample of water was filtered through a filter paper held by a glass funnel in the hopes of removing all solids. More gravel and sand was added to the previously filled Styrofoam cup in an attempt to further separate the oil from the water and remove all visible impurities. This trial was unsuccessful because the ending solution was quite milky in appearance, with too much sediment and solids present. It was inferred that this result was achieved because there had not been filter paper placed on the bottom of the Styrofoam cup at the start of the experiment, as there had been in the first trial. Day three of the lab was a very busy and important day for the lab group. Again, in the fourth trial, the oily water was filtered through the Styrofoam cup. It was decided that a larger scale trial for this method was needed. More gravel and sand was added to the bottom of the cup, along with more filter papers at the base. A greater volume of water was also used for the test. Through the filtered glass funnel and the cup, 125 mL of dirty, oily water was poured. This process took less than five minutes and the result was 77 mL of nearly oil-free water with minimal sediment. This resulting water did have some traces of sediment and murkiness, so it was filtered with another filter paper in a funnel in our next trial. To this funnel, a small pinch of charcoal was added to see its effect on the water. This filtering decreased the volume of water from 77mL to 75mL, but the resulting water was considerably clearer than before. On day four of our lab, there was only about 20 minutes to work with the trial. During this time, charcoal was added to the sample in an attempt to clear the water of its yellowish tint. At 8:26 a.m., 75 mL of the yellowish water was filtered. This sample was poured through a funnel containing a folded filter paper and two pinches of charcoal. This method made the water considerably cleaner--clearing most of the yellowish tint - but some charcoal did fall through the funnel, which made it have a blackish tint. It was planned to filter the charcoal out of the water the next day when there was more time for experimentation. It was also proposed to start a full-scale model of the method. On day five, a new trial began. 142 mL of the foul water was filtered through the Styrofoam cup with a filter paper, gravel, and sand (from bottom to top). This process took 80 seconds and resulted in 90 mL of almost complete oil and sediment free water, though murky and not clear. We filtered this through another filter paper and funnel which took 9 minutes and 40 seconds. 80 mL resulted after this filtering and is clearer than before. After this, 4.9 mL of charcoal was added directly into the water and swirled this in a beaker for 30 seconds. Again, the charcoal and water mixture was filtered through a filter paper to remove the charcoal and came out with 22 mL of considerably clearer and cleaner water. However, the resulting substance was not a pure compound of the elements hydrogen and oxygen (water). The result after filtration was a homogeneous mixture in which the salt in the water could not be physically observed, but was clearly present because one could taste it in the sample. On day seven, a distillation apparatus was used to finish the purifying process and completely remove any bacteria, salt, or sediment from the solution, in other words to derive the pure substance (compound) of water from this mixture. This apparatus included a ring stand and a utility clamp to hold a Florence flask. The water was held in the flask and brought to a boil by the Bunsen burner beneath it. The steam from the boiling water was condensed and collected in a graduated cylinder, leaving the impurities behind. This process removed all of the salt that was still present in the water. The trial began with 22mL of water and resulted in a 15 mL after the distillation. The distillation took 120 seconds to be completed (the distillation is completed when the water droplets fall less frequently than they previously had) and left behind a large amount of salt. Only now was this substance truly pure water. Overall, the experiment was precise because all of the times, observations, and steps were recorded. As a result, this experiment is reproducible.
Trial 1:
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Filtering a new water sample through funnel with filter paper into Styrofoam cup with gravel and filter paper
Overnight
50mL
Water is murky, filled with small particles, oil, yellow in color and has a strong odor
28mL
All solids are removed from water, which is still murky in color, has an odor and oil
Trial 2:
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Slowly pouring the 37 mL of water from Trial 1 into a beaker to try and remove the oil on top
10 seconds
37mL
Water is murky and has a plethora of oil circles floating on top
37mL
Water in beaker is identical to the initial sample
Trial 3:
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Filtering a new water sample through funnel with filter paper into Styrofoam cup filled with gravel
3min 27 sec
110 mL
Water is murky, filled with small particles, oil, yellow in color and has a strong odor
93mL
Large particles are removed, but water is still very murky in appearance with sediment floating throughout
Trial 4:
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Filtering a new water sample through funnel with filter paper into Styrofoam cup filled with gravel and filter paper
4 min 53 sec
125mL
Water is murky, filled with small particles, oil, yellow in color and has a strong odor
77mL
Water is mostly oil-free and contains minimum sediment, yet is still murky in appearance
Trial 5:
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Filtering the resulting 77mL of water from Trial 4 through a funnel with filter paper and a few pinches of charcoal
7min 10 sec
77mL
Water is mostly oil-free and contains minimum sediment, yet is still murky in appearance
75mL
Water is considerably clearer but retains its yellow tint. The sample is basically oil-free and odorless.
Trial 6:
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Filtering the resulting 75mL of water from Trial 5 through a funnel with filter paper with about twice the charcoal used in Trial 5
8min 6 sec
75mL
Water is considerably clearer but retains its yellow tint. The sample is basically oil-free and odorless.
70mL
Water has lost its yellow tint – due to charcoal falling through the funnel though, it has a black tint.
Trial 7:
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Filtering a new sample of water through a Styrofoam cup with filter paper, gravel, and sand
80 seconds
142mL
Water is murky, filled with small particles, oil, yellow in color and has a strong odor
90mL
Water is almost completely oil and sediment free, although murky
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Filtering the resulting 90mL from Step 1 through a funnel and filter paper
9 minutes 40 seconds
90mL
Water is almost completely oil and sediment free, although murky
80mL
Water is considerably clearer than before, but still opaque
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Adding 4.9 mg of charcoal to the 80mL of water resulting from Step 2 and swirling the beaker
30 seconds
80mL
Water is considerably clearer than before, but still opaque
80mL
Water has a black tint as it is filled with particles of charcoal
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Filtering the 80mL of water and charcoal through a funnel with filter paper
7 min 5 sec
80mL
Water has a black tint as it is filled with particles of charcoal
22mL
Water is clear, oil-free, and odorless
Procedure
Approx. Time
Initial volume (mL)
Observations before procedure
Final volume (mL)
Observations after procedure
Boiling 22mL of water and collecting the condensation droplets
120sec
22mL
Water is relatively clear, yet is still not fully transparent
15mL
Water is 100% pure clear, oil-free, and odorless
3.)Calculations: To calculate if this process will produce enough water for the 3 survivors to survive each day, first it was researched how much water was needed for an average women to survive. The result was 8 cups, or about 1,893mL. For three people, this comes to 5,678mL per day to be filtered. The percent yield of this experiment was found by calculating the final volume of pure water divided by the beginning volume of foul water and then multiplied by 100. The beginning volume of foul water in our last trial was 142 mL and after several steps of filtration, the final volume of clear water was 22 mL before distillation. It is known that out of 73mL of water, 50mL was left after the class distillation. To find the percentage of distillation, the equation 50mL (resulting volume) / 73mL (starting volume) = about .68 .68 x 100 = 68% is performed. This equation shows that overall, the results of the distillation process are about 68% of the starting volume. Using this model, the volume of our resulting water sample can be calculated. 22mL (starting volume of distillation) / .68 (percentage left) = about 15mL Thus, the final volume of clear water after distillation is 15 mL.
To calculate the total yield of the experiment, the equation
15mL (resulting volume) / 142mL (starting volume) = about .105
.105 x 100 = 10.5%
is performed. Thus, after extensive experimentation, the total yield of purified water was %10.5 of what the group started with. Before the start of experimentation, it was calculated that each survivor on the island would need 8 cups, or 1,893mL in order to survive each day. As this would only be the final result, the proportion can be set so that 5,678mL is %10.5 of the starting water sample. 10.5 / 100 = 5,678 / x Following this math, the starting water sample would need to be about 54,076mL. As it took the group a total combined time of 20min 35sec to purify 142mL of water, a proportion would show that it would take the group a total of 5 days, 10 hours, 38 min and 28 seconds to purify 54,076mL. 1235seconds/142mL = x seconds / 54,076 Thus, it can be seen that using the methods performed in the laboratory, the survivors would not be able to filter water at a sufficient rate (54,076 mL per day) to survive the island.
4.)Discussion: The overall goal of the lab was to purify the water. All members of the group contributed to constructing a hypothesis based on the given information before the experiments began. As the trials occurred, changes to the hypothesis were made. Error and results of the trials also influenced the decisions made by the group to alter parts of the experiment to make it successful. The original hypothesis states: The foul water can be purified by removing solids and oil from the solution by pouring the water through filter papers and a Styrofoam cup filled with sand and gravel, and the end result will be boiled. In this original hypothesis, it was planned to remove the oil and solids through the Styrofoam and the rest of the impurities (salt, bacteria, dead organisms) through boiling. This hypothesis changed throughout the experiment. The goal of Trial 1 was to remove large particles of sediment and the oil from the foul water through the Styrofoam cup and filter papers. This was successful--almost all of the sediment/solids were removed but their was still some oil present in this heterogeneous mixture. To remove the remaining oil, the group decided to separate the oil from the water by pouring the oil off the top of the bottle - Trial 2. This proved unsuccessful because oil’s density is less than water’s density, and as a result this pure substance will always float on top of water. After this failure, the lab group decided to go back to the first method tested, thinking that if a small amount of rocks removed some of the oil, a larger amount would probably remove a larger amount of oil. In Trial 3, the goal was to separate the oil from the water, as well as the solids present in the new sample. This trial was successful in removing most of the oil from the mixture, but many solids remained as the group failed to repeat the first Trial exactly - there were no filter papers on the bottom of the cup. Thus, the goal of Trial 4 was to redo Trial 3, except adding a few additional filter papers to the bottom of the Styrofoam cup and the glass funnel to ensure that all sediment was removed. This was successful because the solids are removed by the filter papers, and most oil by the rocks, but the water still had a murky appearance. In Trial 5, the group took the result of Trial 4 and added a small amount of charcoal. The goal of this was to remove the water’s murky appearance and make it fully transparent. The result was considerably clearer water, but it still had a yellowish tint to it. In Trial 6, the results of the previous trial was filtered through a filter paper containing more charcoal. The goal was to remove the yellow tint and make the water completely clear. This was successful in that the yellowish tint was removed, but the water then had a blackish tint because some of the charcoal had unexpectedly fallen through the filter paper into the water. From here, the group looked at their observations. Trial 7 was a full scale trial based on all of the revisions made to the experiments by the group members. All previous errors and mistakes were taken into consideration while making this trial. The goal of Trial 7 was to remove all oil, solids, and murkiness from the new sample. First, the water was filtered through the Styrofoam cup filled with filter papers, rocks and gravel to remove all visible solids (organic material) as well as oil. Next, the water was filtered through a single filter paper to remove smaller sediment. The remaining sample was then mixed with charcoal, as this procedure had proved to clear the water previously. The new charcoal/water substance was then filtered to remove the charcoal, resulting in visibly clear water. Finally, this water was boiled to remove any salt and bacteria present. In this final trial, the group used observations and techniques gathered from all previous trials to perform a full-scale water filtration and distillation.
The hypothesis was revised many times during the experiment as error occurred and as changes needed to be made in order to successfully purify the water. For example, in the beginning, the group was not sure about how the charcoal could be used. By learning from their classmates’ trials, it was realized that the charcoal could be used to purify the water and make it clearer. This change to the experiment was made. Also, the group realized that their clear water could not be just boiled, but an apparatus was needed to collect the condensation of the boil. Without this, only the leftover salt and sediment would remain and the water would evaporate into the atmosphere. It was an important realization. Through personal knowledge and learning from classmates’ photos on the Wikispace, the appropriate changes were made to the hypothesis to make the successful.
Error was also a factor taken into consideration. Error could have occurred throughout these trials due to incorrect measurements. Although all measuring of liquid substances was done in graduated cylinders, room for error must be left. It is hoped that our experiment was precise as all of the data and measurements were recorded so the procedure would be able to be reproduced. As there are no known measurements to compare the results to, we can not be sure of their accuracy, but it is hoped that future tests will produce close results to prove these conclusions accurate.
In conclusion, the yield is not and should not be expected to be 100% as much water was lost in the filtration process when it was stopped by sand, gravel, charcoal, etc. Also, much of the starting volume consisted of oil and solids, which were extracted before the ending sample was measured. In addition, since the experiment was not performed all in one day, some water could have evaporated overnight and could have tampered with the accuracy of the results.
5) Conclusion
Overall, the lab group was successfully able to purify the foul water sample. The results of the filtration and distillation procedures left the pure compound, water, in place of the heterogeneous mixture that was its processor. Some of the trials performed, such as the filtration in the Styrofoam cup, the mixing with charcoal, and the distillation proved incredibly effective in removing dirt, oil, bacteria and salt from the sample. Other trials, such as the pouring of the sample to remove the oil, did not prove as effective. Looking back, another trial is believed to may have been beneficial - a medicine dropper could have been taken to suck up and remove the oil floating on top of the foul water. Yet, the lab group is content with the procedures and believes that the experiment was performed in the most efficient way possible, as little resources were wasted and all of the trials gave important insight and aided in drawing conclusions. Throughout this process, all members of the lab group worked well together, sharing roles and working to reach the goal of purified water. All members of the team worked quickly and contributed to the ideas for experiments and solutions. All in all, the foul water lab was an equal effort by all team members, and the successful results of the experiment directly correlate to the hard work put in by each participant.
Julia Tolmachyov, Francesca Cali, Galen O’Neill
1) Introduction
Throughout this lab, the ultimate goal was to completely filter and purify all organic matter, dirt, bacteria, and harmful substances in the water available to us in order to survive on the desert island.
Undoubtedly, there were many substances in this water that could be harmful to the body. Most likely, the water was filled with dirt, dead organisms, bacteria, algae, etc. Oil and solid materials were also detected in the water. Again, our goal is to remove said impurities. Based on our hypothesis, we planned to purify the water with a method using all available resources. This included filter papers, gravel, sand, charcoal, and fire. We planned to filter the water’s large particles through the gravel and sand, the filter paper will separate these into the smallest possible particles. We plan on adding charcoal to the filtered water to make it clearer. This remaining sample will be boiled to kill all harmful bacteria.
Hypothesis: The foul water can be purified by pouring the water through filter papers and a Styrofoam cup filled with sand and gravel, and the end result will be boiled to remove all solids and impurities
2) Procedure/Data/Observations
For the first trial of this experiment, it was decided to first drain a sample of the contaminated water to remove any visible sediment. First, the Styrofoam cup was taken and its contents--gravel and sand--were transferred into a small beaker to hold. Three holes were punched in the bottom of the cup, which was used to drain the water. Next, a piece of filter paper was placed at the bottom of the cup so that all liquids filtering through the Styrofoam would eventually come in contact with and go through the bottom filter paper. Since there was unlimited gravel and sand, the cup was filled about ¼ of the way up with gravel rocks, and ¼ up with sand, in order to help drain and filter the foul water. Because there was only a limited amount of charcoal, this resource was not being used until it was certain that this filtration method was successful. An iron ring attached to a ring stand was used to hold a glass funnel in place over the Styrofoam cup, which itself was nestled in a beaker in order to catch the filtered water. Another filter paper was placed in the glass funnel. 50 millilitres of the foul water was poured into this glass funnel through the filter paper. The water took a very long time to drain completely, so it was left to drain throughout the day.
On day two of lab, several new methods to purify the water were tried and observed. At 8:00 a.m., it was found that the trial from day one--the Styrofoam cup filter--helped remove all solids from the solution, but it did not separate the water from the oil present in the mixture. This was a problem because not only was the water still not safe to drink, if one attempted to boil this substance, it would combust, thus ruining the trial and wasting important resources. The first trial of day two attempted to separate the water and the unwanted oil in the filtered sample. Since oil floats above water in this heterogeneous mixture, the solution was slowly poured out of the beaker in an attempt to separate the oil and water. If this mixture had been homogeneous, the water and oil would not have been distinguishable in the mixture. This trial was unsuccessful because no matter what angle or position the solution was poured, the oil remained on the top, as oil has a density less than water and will always float on the surface. Even though this trial was unsuccessful, no resources were wasted or lost.
In the third trial, 110 millilitres of a new sample of water was filtered through a filter paper held by a glass funnel in the hopes of removing all solids. More gravel and sand was added to the previously filled Styrofoam cup in an attempt to further separate the oil from the water and remove all visible impurities. This trial was unsuccessful because the ending solution was quite milky in appearance, with too much sediment and solids present. It was inferred that this result was achieved because there had not been filter paper placed on the bottom of the Styrofoam cup at the start of the experiment, as there had been in the first trial.
Day three of the lab was a very busy and important day for the lab group. Again, in the fourth trial, the oily water was filtered through the Styrofoam cup. It was decided that a larger scale trial for this method was needed. More gravel and sand was added to the bottom of the cup, along with more filter papers at the base. A greater volume of water was also used for the test. Through the filtered glass funnel and the cup, 125 mL of dirty, oily water was poured. This process took less than five minutes and the result was 77 mL of nearly oil-free water with minimal sediment.
This resulting water did have some traces of sediment and murkiness, so it was filtered with another filter paper in a funnel in our next trial. To this funnel, a small pinch of charcoal was added to see its effect on the water. This filtering decreased the volume of water from 77mL to 75mL, but the resulting water was considerably clearer than before.
On day four of our lab, there was only about 20 minutes to work with the trial. During this time, charcoal was added to the sample in an attempt to clear the water of its yellowish tint. At 8:26 a.m., 75 mL of the yellowish water was filtered. This sample was poured through a funnel containing a folded filter paper and two pinches of charcoal. This method made the water considerably cleaner--clearing most of the yellowish tint - but some charcoal did fall through the funnel, which made it have a blackish tint. It was planned to filter the charcoal out of the water the next day when there was more time for experimentation. It was also proposed to start a full-scale model of the method.
On day five, a new trial began. 142 mL of the foul water was filtered through the Styrofoam cup with a filter paper, gravel, and sand (from bottom to top). This process took 80 seconds and resulted in 90 mL of almost complete oil and sediment free water, though murky and not clear. We filtered this through another filter paper and funnel which took 9 minutes and 40 seconds. 80 mL resulted after this filtering and is clearer than before. After this, 4.9 mL of charcoal was added directly into the water and swirled this in a beaker for 30 seconds. Again, the charcoal and water mixture was filtered through a filter paper to remove the charcoal and came out with 22 mL of considerably clearer and cleaner water.
However, the resulting substance was not a pure compound of the elements hydrogen and oxygen (water). The result after filtration was a homogeneous mixture in which the salt in the water could not be physically observed, but was clearly present because one could taste it in the sample. On day seven, a distillation apparatus was used to finish the purifying process and completely remove any bacteria, salt, or sediment from the solution, in other words to derive the pure substance (compound) of water from this mixture. This apparatus included a ring stand and a utility clamp to hold a Florence flask. The water was held in the flask and brought to a boil by the Bunsen burner beneath it. The steam from the boiling water was condensed and collected in a graduated cylinder, leaving the impurities behind. This process removed all of the salt that was still present in the water. The trial began with 22mL of water and resulted in a 15 mL after the distillation. The distillation took 120 seconds to be completed (the distillation is completed when the water droplets fall less frequently than they previously had) and left behind a large amount of salt. Only now was this substance truly pure water.
Overall, the experiment was precise because all of the times, observations, and steps were recorded. As a result, this experiment is reproducible.
Trial 1:
Time
(mL)
(mL)
after procedure
Trial 2:
Time
(mL)
(mL)
after procedure
Trial 3:
Time
(mL)
(mL)
after procedure
Trial 4:
Time
(mL)
(mL)
after procedure
Trial 5:
Time
(mL)
(mL)
after procedure
Trial 6:
Time
(mL)
(mL)
after procedure
Trial 7:
Time
(mL)
(mL)
after procedure
Time
(mL)
(mL)
after procedure
Time
(mL)
(mL)
after procedure
Time
(mL)
(mL)
after procedure
Time
(mL)
(mL)
after procedure
3.)Calculations:
To calculate if this process will produce enough water for the 3 survivors to survive each day, first it was researched how much water was needed for an average women to survive. The result was 8 cups, or about 1,893mL. For three people, this comes to 5,678mL per day to be filtered.
The percent yield of this experiment was found by calculating the final volume of pure water divided by the beginning volume of foul water and then multiplied by 100. The beginning volume of foul water in our last trial was 142 mL and after several steps of filtration, the final volume of clear water was 22 mL before distillation.
It is known that out of 73mL of water, 50mL was left after the class distillation. To find the percentage of distillation, the equation
50mL (resulting volume) / 73mL (starting volume) = about .68
.68 x 100 = 68%
is performed. This equation shows that overall, the results of the distillation process are about 68% of the starting volume. Using this model, the volume of our resulting water sample can be calculated.
22mL (starting volume of distillation) / .68 (percentage left) = about 15mL
Thus, the final volume of clear water after distillation is 15 mL.
To calculate the total yield of the experiment, the equation
15mL (resulting volume) / 142mL (starting volume) = about .105
.105 x 100 = 10.5%
is performed. Thus, after extensive experimentation, the total yield of purified water was %10.5 of what the group started with.
Before the start of experimentation, it was calculated that each survivor on the island would need 8 cups, or 1,893mL in order to survive each day. As this would only be the final result, the proportion can be set so that 5,678mL is %10.5 of the starting water sample.
10.5 / 100 = 5,678 / x
Following this math, the starting water sample would need to be about 54,076mL. As it took the group a total combined time of 20min 35sec to purify 142mL of water, a proportion would show that it would take the group a total of 5 days, 10 hours, 38 min and 28 seconds to purify 54,076mL.
1235seconds/142mL = x seconds / 54,076
Thus, it can be seen that using the methods performed in the laboratory, the survivors would not be able to filter water at a sufficient rate (54,076 mL per day) to survive the island.
4.)Discussion:
The overall goal of the lab was to purify the water. All members of the group contributed to constructing a hypothesis based on the given information before the experiments began. As the trials occurred, changes to the hypothesis were made. Error and results of the trials also influenced the decisions made by the group to alter parts of the experiment to make it successful. The original hypothesis states: The foul water can be purified by removing solids and oil from the solution by pouring the water through filter papers and a Styrofoam cup filled with sand and gravel, and the end result will be boiled. In this original hypothesis, it was planned to remove the oil and solids through the Styrofoam and the rest of the impurities (salt, bacteria, dead organisms) through boiling. This hypothesis changed throughout the experiment.
The goal of Trial 1 was to remove large particles of sediment and the oil from the foul water through the Styrofoam cup and filter papers. This was successful--almost all of the sediment/solids were removed but their was still some oil present in this heterogeneous mixture. To remove the remaining oil, the group decided to separate the oil from the water by pouring the oil off the top of the bottle - Trial 2. This proved unsuccessful because oil’s density is less than water’s density, and as a result this pure substance will always float on top of water. After this failure, the lab group decided to go back to the first method tested, thinking that if a small amount of rocks removed some of the oil, a larger amount would probably remove a larger amount of oil. In Trial 3, the goal was to separate the oil from the water, as well as the solids present in the new sample. This trial was successful in removing most of the oil from the mixture, but many solids remained as the group failed to repeat the first Trial exactly - there were no filter papers on the bottom of the cup. Thus, the goal of Trial 4 was to redo Trial 3, except adding a few additional filter papers to the bottom of the Styrofoam cup and the glass funnel to ensure that all sediment was removed. This was successful because the solids are removed by the filter papers, and most oil by the rocks, but the water still had a murky appearance. In Trial 5, the group took the result of Trial 4 and added a small amount of charcoal. The goal of this was to remove the water’s murky appearance and make it fully transparent. The result was considerably clearer water, but it still had a yellowish tint to it. In Trial 6, the results of the previous trial was filtered through a filter paper containing more charcoal. The goal was to remove the yellow tint and make the water completely clear. This was successful in that the yellowish tint was removed, but the water then had a blackish tint because some of the charcoal had unexpectedly fallen through the filter paper into the water. From here, the group looked at their observations. Trial 7 was a full scale trial based on all of the revisions made to the experiments by the group members. All previous errors and mistakes were taken into consideration while making this trial. The goal of Trial 7 was to remove all oil, solids, and murkiness from the new sample. First, the water was filtered through the Styrofoam cup filled with filter papers, rocks and gravel to remove all visible solids (organic material) as well as oil. Next, the water was filtered through a single filter paper to remove smaller sediment. The remaining sample was then mixed with charcoal, as this procedure had proved to clear the water previously. The new charcoal/water substance was then filtered to remove the charcoal, resulting in visibly clear water. Finally, this water was boiled to remove any salt and bacteria present. In this final trial, the group used observations and techniques gathered from all previous trials to perform a full-scale water filtration and distillation.
The hypothesis was revised many times during the experiment as error occurred and as changes needed to be made in order to successfully purify the water. For example, in the beginning, the group was not sure about how the charcoal could be used. By learning from their classmates’ trials, it was realized that the charcoal could be used to purify the water and make it clearer. This change to the experiment was made. Also, the group realized that their clear water could not be just boiled, but an apparatus was needed to collect the condensation of the boil. Without this, only the leftover salt and sediment would remain and the water would evaporate into the atmosphere. It was an important realization. Through personal knowledge and learning from classmates’ photos on the Wikispace, the appropriate changes were made to the hypothesis to make the successful.
Error was also a factor taken into consideration. Error could have occurred throughout these trials due to incorrect measurements. Although all measuring of liquid substances was done in graduated cylinders, room for error must be left. It is hoped that our experiment was precise as all of the data and measurements were recorded so the procedure would be able to be reproduced. As there are no known measurements to compare the results to, we can not be sure of their accuracy, but it is hoped that future tests will produce close results to prove these conclusions accurate.
In conclusion, the yield is not and should not be expected to be 100% as much water was lost in the filtration process when it was stopped by sand, gravel, charcoal, etc. Also, much of the starting volume consisted of oil and solids, which were extracted before the ending sample was measured. In addition, since the experiment was not performed all in one day, some water could have evaporated overnight and could have tampered with the accuracy of the results.
5) Conclusion
Overall, the lab group was successfully able to purify the foul water sample. The results of the filtration and distillation procedures left the pure compound, water, in place of the heterogeneous mixture that was its processor. Some of the trials performed, such as the filtration in the Styrofoam cup, the mixing with charcoal, and the distillation proved incredibly effective in removing dirt, oil, bacteria and salt from the sample. Other trials, such as the pouring of the sample to remove the oil, did not prove as effective. Looking back, another trial is believed to may have been beneficial - a medicine dropper could have been taken to suck up and remove the oil floating on top of the foul water. Yet, the lab group is content with the procedures and believes that the experiment was performed in the most efficient way possible, as little resources were wasted and all of the trials gave important insight and aided in drawing conclusions. Throughout this process, all members of the lab group worked well together, sharing roles and working to reach the goal of purified water. All members of the team worked quickly and contributed to the ideas for experiments and solutions. All in all, the foul water lab was an equal effort by all team members, and the successful results of the experiment directly correlate to the hard work put in by each participant.