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MBIS SCIENCE The Boiling Point Of Water With and without salt Arman Jindal 10/14/2011 Lab Report My aim in this scientific investigation was to find out how salt in boiling water affects the time and temperature it takes to boil. Then I would compare the two sets of data I collected from the two experiments and compare to see how. Research question “How does salt and other compounds affect the time it takes to get water at its boiling point” My background information The boiling point: In liquid, molecules are packed closely together with random movements. As we heat the water the temperature rises and then there is lots of vibration. As the molecules vibrate and they go into a molecular motion which looks like moving a lot they slip past each other which then allow water to become gas. Water boils at 100 degrees Celsius (at sea level). As you boil water at higher places above sea level the boiling point is lower and if you boil water at a place below sea level the boiling point will be higher. This is due to the fact that if you are lower than sea level the atmosphere pressure is higher so therefore it takes longer for the water to boil. These two points are linked because when there is less pressure in the atmosphere then there is nothing restraining the molecules from vibrating. Hypothesis I think the salt in the water will pose as an obstacle towards the vibrating molecules, just like the pressure in the atmosphere. This results in a higher temperature to take water to its boiling point. I think that it would be difficult to maintain a temperature of 100 degrees Celsius with distilled water because we are above sea level. With the salt (NaCl) I think it will take a greater temperature to boil due to the fact it takes more space. Variables Independent variable: salt because it is simply what we are testing. Dependent variable: boiling point Constant variable: The amount of water in each beaker Materials Stop watch Measuring cylinder (100ml) Beaker 30% Salt (NaCl) Wire gauge Electronic heater thermometer Tongs Tripod stand Bunsen burner Safety procedure This experiment has various harmful and hot things such as the Bunsen burner and the water that is going above 100 degrees Celsius. We wore aprons incase the beaker spilt or fell and we wore glasses as a normal safety procedure. We have to be extra careful here because we are dealing with fire. In case something happens I would run immediately and turn the gas off. There is also the fire extinguisher on the door. Procedure We first got our help sheet to give us some guidelines. My partner was Sandip, Ms. Maya gave us the 30% salt mixed with water already so all we had to do was take 100ml. We used the tripod with the special sheet to prevent any equipment we used to be affected by the flame. I lit the Bunsen burner (with a certain degree of safety) we took readings every 1 minute for both experiments. Sandip and I drew up tables and graphs so we could present our findings in the best way possible. Boiling point of water with salt Difference Boiling point of distilled water Data and observation Minutes 1, 5 degrees Temperature 1 38.7 Minutes 2, 3.4 degrees 2 45.6 Temperature 1 33.7 3, 8.1 degrees 3 58.1 2 43.2 4 62.9 4, 2.3 degrees 3 50.0 5 74.5 4 60.6 5, 6.7 degrees 6 80.0 5 67.8 6, 1.2 degrees 7 86.4 6 78.8 8 91.0 7, 3.3 degrees 7 83.1 9 95.4 8, 1.5 degrees 8 89.5 10 99.3 9 91.8 9, 3.6 degrees 10 98.2 10, 1.1 degrees 100 90 80 70 60 Tempreature of salt water 50 Tempreature of water without 40 salt 30 20 10 0 1 2 3 4 5 6 7 8 9 10 11 12 13 Analysis of Data I found that our readings were reliable and the graph shows the difference. It took nine minutes for the water without salt to start boiling vigorously and it took 11minutes and 47 seconds. I have seen the differences and was astound at how close they were in temperature but boiling wise I knew that the distilled water would start boiling vigorously a lot sooner than the other group. I think that from the data I could see the difference in the beginning. The water would take off but as the distilled water neared its boiling point but it started boiling a lot faster. The difference in the two were 1 because of the altitude and 2 because the other one had salt which leashed the vibration and molecular which needs more heat. Conclusion My hypothesis was more or less correct; I observed the data and understood the tables and results. The hypotheses passed the secret for me to understand why the distilled water started boiling faster at 9 minutes and the salt water took 11 minutes and 45 seconds to start boiling. I would say that this science investigation was a success even though we didn’t take results two times. This investigation really showed me how much salt can really affect water at its boiling point. Therefore I conclude that salt and other compounds affect at which the temperature it takes to boil water by simply blocking the molecules from turning into gas.
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