Colin's+Lab+Report

Introduction: Our plane has just crashed on a deserted island. The weather is hot and sunny, there is no drinkable water on the island or in the surrounding sea. We have 128 water bottles, but that is not enough to keep us alive forever so we must try to make our own. We have 5 people in our group, me, David, Katie, JJ, and Ben. We must purify the water to survive, and that was our goal. Our hypothesis is that we must use the sand and charcoal to make the water clear of oil and sediment, then boil to kill any bacteria that is in the water.

Procedure: On the first day of our experimentation we used sand and charcoal.The purpose of the sand was to absorb particles of dirt and oil, and the charcoal was used to filter out the remaining bigger particles. This would go through filter paper and a funnel, to help seperate the sediments and such. This would all be drained into a beaker, where it would also be boiled. We proposed this plan to Mr. Nilsen, where he pointed out a major flaw. The sample of water contained oil, which automatically meant that we could not boil it yet. So to drain the oil, we used a styro foam cup with a very small hole and placed it under the funnel. The purpose of the hole was to let water drain through while the thicker oil would sit in the cup without dripping down. We used 100mL of water, 20mL of sand, and 5mL of charcoal. On the second day we tested this idea. It worked well, but it no where near perfect. We used all the same materials as day 1, but we used only 60mL of water so we did not waste any sample. The water was pretty murky, with yellow tint to it. We knew that it was not completely cleansed of oil and sediment. Using a graduated cylinder and scale, we were able to find the liquid has a volume of 62mL, mass of 43.99g, and a density of 1.409mL/g. This was not yet pure water because pure water has a density of 1. To attempt to get out the excess oil and sediment, JJ added rocks. To the surprise of the group, it was just what was needed. After adding the rocks we found that the volume was 37mL, the mass was 38.2g and the density was 1.038 mL/g. This was a much better result. Our volume and mass was lower becuase we did lose some water from our previous attempt when we dumped it out instead of letting it drip. On the third day we removed the sand because it was causing the murkiness. Now we used only 1/2 teaspoon of charcoal, 22 rocks, and 62mL of water. This was what we had been looking for. But even with the good filtering system, it was impossible to filter out all of the oil, so we needed to find out how much there was before we could hand it over to Mr. Nilsen. We found that it had a volume of 20mL, mass of 12.66g, and a density of .633g/mL. We did not boil the water this day because we did it as a class later in the week. During this Mr. Nilsen used a series of flasks and tubes, boiled the water at a lower temperature so that the glass would not explode because of pressure. After this we had distilled (pure) water.

Procedure Time/Oberservations: The first test using the sand, charcoal, and filter took a total time of approximately 15 minutes. The water in this experiment as I stated before came out very murky, because of the sand. There was still 60mL of oil also, because we had not yet applied the rocks to the experiment. On our second try we then used the filter paper and charcoal for 10 minutes. Because of human error, the filter paper failed (Katie). As a result we had black water. We reattempted it however with less water, and came out with clear water. The test had worked.

Calculations: Our good water had a density of 1.038mL/g. The yield of the test was 62%. After boiling it in the special way we 100% pure water.

Discussion: Our goals of this project varried depending on what problem occurred after each test until the water was finally clear. Our first goal was to seperate oil and sediment using sand and charcoal. Immidiately, Mr. Nilsen pointed out the problem with the filtering the oil. This is when were able to place the styrofoam cup. After this we removed most of the oil, but the water had a very murky composition. We interpreted that this was oil that was sitting on the top of the mixture, and acted by placing the rocks into the funnel. This helped eliminate even more oil, but still we found that the solution was coming out murky. So we eliminated the sand hoping that the charcoal would not turn the mixture black and could still filter out all of the mixture. This worked perfectly because all color and sediment were taken out of the mix. We also found that the rocks were not needed and that they were now adding unwanted sediment to the water. With this project, there was a lot of trial and error, which means that while we did not always do the right thing we were able to gradually get the desired results.

Identify: We were able to successfully identify most of the substances within the mixture. We immidiately were able to identify that oil and sediment were present. The oil was clearly visible because it has a higher density than the water, it sat above it. The sediment was also clearly visible because it turned the water almost dark brown. Also, as tests went on, we could identify materials that we were using to purify the water would sometimes mix in with the water.

Analyze: The yield can never be 100%. This is because every time we filtered the water with the materials whether it be sand, charcoal, rocks, or even filter paper, some water is always lost. Some human error also occurred, so water was lost, but even so, the yield could never be 100%.

Conclusion: As a group we were successful in accomplishing our goal as we did at the end of the experiment come up with completely pure drinking water. While we may not have been as efficient as we might of wanted to be, mostly due to the fact that at some times a member of our group would not participate as he or she needed to, we still were able to get the right procedure eventually.

Describe: A lot of changes were made throughout the whole project, but the most important was the styrofoam cup, and the fact we changed to strictly using charcoal for filtering. Mr. Nilsen gave us the idea for the plastic cup, but we got the idea for the charcoal from other groups where it worked very successfully. I only wished we did this earlier, that way we may have achieved our goal even faster.

Discuss: I think for the most part work was very evenly divided with the exception of the person I mentioned earlier. But as a whole, We enjoyed working with the other members of the group because I can say that they were very serious, and wanted to succeed.