Chris


 * __Measuring the affects of pollutants upon levels of dissolved oxygen in water__**

Chris Hosking, Nick Fabiano, Freddy Cavallin. In our modern world, pollution, global warming, desertification and the rate at which animals are dying, are all closely linked. Our investigation was to see the effects that pollutants have when put into an aqueous solution. We wanted to simulate the effects pollutions dumped in fresh water seas or the oceans would have. Our results will focus specifically on the level of dissolved oxygen in the water, as many underwater creatures depend on a specific level to flourish. During this investigation we aim to; learn how to use a Vernier dissolved oxygen probe with a LabPro interface, measure the differences in levels of dissolved oxygen after the addition of Magnesium to the water, and to relate our finds to what is currently happening in the world. We expect that our materials will collect some data which will show small changes in the water which will seem small to us but are actually large when put on a global scale. We will be using a Lab Vernier probe which is highly accurate when used correctly - so it’s an all or nothing investigation. Our probe will measure the dissolved oxygen which is in milligrams per litre. Our investigation will be divided into two parts, the first to make sure we can accurately use the probe, and the second to actual measure the affects a pollutant has on water.
 * __Introduction__**

LabPro interface Vernier dissolved oxygen probe (2) Vernier temperature probe Laptop Weighing machine Hot plate with magnetizing control Capsule magnet stirrer Clamp stand Beaker Magnesium (Mg) Water (H2O)
 * __Materials__**

//(An introduction to Part I of our investigation)// //Part I// of our investigation was specifically an experiment using the dissolved oxygen (D.O.) probe to measure the changes in oxygen levels as the water was heated. We chose this experiment so that we could understand how to best use our materials and how to graph them. Before even starting //Part I// however, we simply put our D.O. probe into water. The results from this were highly erratic. We received mixed data as the D.O. probe recorded a fluctuating level of D.O. levels which was unusual. After researching our D.O. probe we found that it only worked if the solution it was placed in was in constant movement, and this is was when we introduced the magnet stirrer (The magnet is placed in the solution, and then spins and creates a continuous flow of solution by our D.O. probe.) Our data records after putting in the magnet were all perfect, with the level staying constant as we didn’t put the water under any special conditions. As a caution though, we added a second D.O. probe to make sure the probe wasn’t just sending us false data. When we added the second D.O. probe, we then received the same data from both probes when they were in the same solution. This investigation does not include our original data as we were learning how to use the probe effectively, as //Part I// was our final stage of comprehension in using the D.O. probe with the LabPro interface.
 * __Preparation__**

//__Part I__//
 * __Method/Procedure__**


 * 1) Get out all the necessary materials as seen above (Hot plate, beaker, water, capsule magnet, 2 D.O. probes, temperature probe, clamp stand, LabPro interface and a laptop.)
 * 2) Fill the beaker with water and drop the capsule magnet inside. Put the beaker on the hot plate.
 * 3) Connect the LabPro interface to the laptop and hook up two D.O. probes and one Temperature probe. Then open the Logger Pro program on the laptop.
 * 4) Using the clamp stand as a rest for the cables of all the probes, lower the probes into the water.
 * 5) Start calibrating information on the laptop and turn on the temperature and the magnet stirrer of the hot plate.
 * 6) Turn off the stirrer and temperature of the hot plate after temperature readings hit 40 degrees.
 * 7) By now the set-up will look like the picture above.
 * 8) Graph the change in D.O. levels in the water in comparison to the temperature of the water.

//__Part II__//


 * 1) Get out all the necessary materials as seen above (Hot plate, beaker, water, capsule magnet, 2 D.O. probes, clamp stand, LabPro interface, magnesium and a laptop.)
 * 2) Fill the beaker with water and drop the capsule magnet inside. Put the beaker on the hot plate.
 * 3) Connect the LabPro interface to the laptop and hook up two D.O. probes. Then open the Logger Pro program on the laptop.
 * 4) Using the clamp stand as a rest for the cables of all the probes, lower the probes into the water.
 * 5) Start calibrating information on the laptop and turn on the magnet stirrer of the hot plate.
 * 6) Add magnesium powder to the water.
 * 7) Set up at this point should look like the picture above.
 * 8) Record and graph results.

Our expectations were, that through this investigation we could better comprehend the effects that some pollutants have on mass bodies of water. We had in mind the idea that some pollutants must scavenge the water of its D.O. which various marine life depend on. We set our investigation around placing an oxidizing metal into water and recording the effect on the D.O. content of the water. We believed that by placing an oxidizing metal into water we would simulate actions that happen when oxidizing pollutants enter a body of water. We expected clear and measurable changes in the D.O. level after the reaction with the oxidizing agent (in this case Magnesium.) //Qualitative Observations// · We found that using a D.O. probe just in water, would produce highly erratic results that always fluctuated. · We saw that the D.O. probe functioned properly when used with the magnet stirrer. · We were able to see a definite drop in the levels of D.O. in the water in both //Part I// and //Part II// of our investigation. //Data Processing and analysis// The first graph from //Part I// shows the data we received whilst testing the D.O. levels in water while we heated it. As you can see the D.O. level drops as time goes on and the temperature increases. We believe that the pressure between the H2O molecules change with temperature and perhaps a higher temperature has a higher pressure which doesn’t allow for D.O.. As you can see, our results from //Part I// are highly accurate and further investigation would probably be able to establish a linear relationship between levels of D.O. in water and the temperature of the water. I believe that our performance during //Part I// was perfect as we accomplished what we set out to do, which was to better comprehend how to use our materials in the best possible way for latter experiments. We repeated //Part II// three times so as to collect a large amount of data to analyze. The first graph was our first time running the experiment and the data from one of the probes from the second try. [During our second try we didn’t see until too late, that one of the probe was touching the glass which corrupted its data intake] Our first graph shows the data taken from three different probes and they all received similar data that when the magnesium was added, D.O. levels did lower. The data also show the D.O. levels trying to stabilize and return to normal after a while. Since Magnesium oxidizing is a chemical reaction which doesn’t reverse - I think that perhaps the motion of the magnet stirrer might have mixed in new oxygen and thus raised the D.O. levels back to normal again. Our final graph is the third time we tested //Part II//. As you can see, the benefit of having two probes is clearly shown as they almost exactly mirror each other throughout the experiment. As with our first trials of //Part II// our data showed that after the addition of Magnesium there was a definite drop in the D.O. levels in the water. Our expectations were proved correct that a reducing agent like Magnesium would oxidize in the water and thus lower the levels of D.O. found in the water. However, as with our first trial we saw that the D.O. levels began to rise after the initial fall.
 * __Expectations (Experiment)__**
 * __Results__**
 * //__[Tables cant be properly pasted on a wiki spaces. Graphs and pictures face similar problems]__//**


 * __Discussion__**

Before commencing our investigation, we expected that //Part// II would be able to help us start to understand some of the effects pollution has on water and what that means on the larger scale for us. We wanted to specifically look into the levels of D.O. in water, and after our //Part II// I think its safe to say the we have been making large steps in that direction. Originally we wanted to go further with our investigation and perhaps graph the different reducing agents and their effects on the D.O. levels, but we ran out of time for this in-depth study. As mentioned in the observations, we saw the D.O. levels rise for reasons unknown, but I believe that perhaps this phenomena can be attributed to the magnet stirrer aerating the water. Going into the investigation we didn’t really know what to expect the graphs to eventually look like, as we had never graphed a chemical reaction beforehand. Because of this fact, I think our group had new understanding of many elements of our investigation. Thanks to //Part I// and the experiments predecessor to it, we were able to understand how best to use the D.O. probe. As this investigation was quite like a pilot investigation for us, using materials we hadn’t used in the past on a subject we knew little to nothing about, there are many questions that have sprung from our investigations and there are further experiments which would now be interesting to carry through, to elaborate on our data. Obviously a question stemming of our investigation was why did the D.O. levels begin to rise after the initial falls? Another question that would be interesting is to elaborate on //Part I// and see if the relationship between temperature and D.O. levels is linear or not. I think that if we had more time that our investigation could have been furthered if we started testing with other reducing agents such as Iron and Sodium. We also didn’t specifically look at how a lower level in D.O. would affect some marine life.


 * __Appendix I: Scientific Terminology (Was supposed to be provided by nick. )__**
 * This should look like a glossary that you would see at the end of a textbook (check your textbook for an example of the format). Terms should be in alphabetical order and be written in **bold face**
 * Each term should have an etymology, a formal definition, and an example sentence in your own words showing how the term is relevant to your investigation
 * In biology, there are generally many new terms. If you have listed less than 20 terms, there are probably too few.


 * __Appendix II: Key Concepts, Models, "Big Ideas" (Nick’s part. Freddy has an std.)__**
 * There will be several "big ideas" that are important for your investigation. Make a list of these ideas (also called "key concepts" in your textbook) which are relevant to your investigation. The list might look like a short table of contents in a textbook.
 * For each big idea, include a diagram (you may make your own or find appropriate diagrams from the internet). Diagrams should be labeled and include captions. THE CAPTIONS MUST BE IN YOUR OWN WORDS!
 * In addition to the diagram, you should include a paragraph that explains how the big idea is relevant to your experiment.
 * __References__**
 * Miller KR, Levine JS. //Biology.// Upper Saddle River, New Jersey: Prentice Hall; 2006: Page Numbers go here.