Lab Essay, Research Paper
Introduction: The purpose of this lab was to introduce a basic scientific method of a chemistry experiment. Approaches of procedural, experimental, and observational methods were explained and introduced to the class. For this lab a “system” was given to identify. Three goals were trying to be accomplished: What the “system” does, what it did, then tell how this was solved after observing it. When writing this lab these principals were to be demonstrated. A hypothesis was made to try to identify the three main goals. The hypothesis made for the “system” was that there are two liquids inside the test tube and if altered will cause a chemical change resulted by the creation of bubbles. Methods: This lab was taken place in Mr. Pierre Bouthyette’s laboratory in room 112 on Tuesday, September 8th. The time the lab was started was 3:13pm. After placing all work materials down at a lab station a “system” was removed from a test tube holder located in the hood at the front of the room. The “system” was brought back and placed down on the lab counter where working materials were. A pair of lab goggles were retrieved by students and placed over their eyes for protection from the “system” if spilt. The first thing that was done was to record all observations of the “system” without touching it or doing anything to it. There were questions that were to be answered such as ” What was the solution standing on?” What did the “system” look like?” “What was the shape of the “system?” Goals were made to try to solve the hypothesis made by the observer. “What would happen if the “system” was heated?” “What would happen if the “system” was cooled?” ” What would happen if the “system” was shaken?” ” Would the “system” change if the test tube was opened?” All of these questions were answered by testing them in a scientific manner. Procedure: Anything could be done to the system as long as the observer realized that it could possibly alter the “system.” All procedures were to be made in a scientific manner, recording all data and recording all timed events. First the “system” was observed without touching it, all data was recorded and a time was recorded. Then it was picked up and lightly shaken, any changing of the “system” was recorded as well as the time. By shaking the “system” it was moved in a vertical motion by one finger placed on the cap and the other fingers placed along the side of the test tube. The “system” was then shaken a bit harder and observation were noted. To be real scientific a standard shake was made and a graph was created to demonstrate change in the “system.” The number of shakes verses the amount of time taken were plotted. If there was a change in color to the “system”, then a graph was plotted to show the intensity of color verses the amount of shakes made. All data was recorded in this procedure. A general time was taken to show how much time had passed since the experiment started. Next, the sound of the “system” was recorded by way of taking a pencil to it and tapping. Then, the system was shaken and the pencil was tapped against it again. The sound was once again recorded. Now the “system” was subjecting to a method of cooling. An ice bath was made by taking 50% ice, 50% water and placing it into a Styrofoam container. The test tube supporting the “system” was placed into the bath, bottom going in first. Time was recorded for how long it stayed in. All changes, if any, were recorded in a data log. After the “system” was taken out, test were made to it. It was shaken to see if there were any physical changes that might be different since it was cooled. Comparisons and contrasts were made from results that were recorded earlier. Next, the “system” was placed into a boiling beaker of water that was on a hot plate. Using test tube tongs, the “system” was held into the water for two minutes, then removed. Any changes in physical appearance were recorded. Other tests were performed to note changes. The test tube was shaken again, and data was recorded. These results were compared and contrasted with earlier data. Then it was time to open the “system” and expose it to the air. The cap was twisted off and dried with a paper towel. The top of the test tube was dried as well. With a wafting motion, the “system’s” odor was observed then recorded. To see if there were any changes that would alter from exposing the “system” to the air other tests were made. The cap was placed back on and it was shaken again. Observations were made and recorded. The “system’s” volume was then changed. Measuring it with a graduated cylinder the volume was recorded. Next, water was added, being the same volume of the “system.” Thus, it became double
Results: The time the experiments started was ( 3:05 ) The “system” was a yellowish colored liquid that had small particles floating around inside. Most of these were collection the bottom of the test tube. When the “system” was placed beside a white piece of paper it became a more intense color. The liquid was clear in color, meaning that it was possible to see through the test tube. When placed behind a black background the “system” was harder to see. Every time the “system” was moved the particles inside shifted. When the test tube was shaken the liquid changed to a light blue color, almost being violet. ( time was 3:13 ) Bubbles were created in the process. It seemed that when the bubbles busted it released a substance that fell back to the bottom. When this substance fell the bluish color appeared. The harder a person shook the “system” the more intense the color became and the longer the time it took to disappear. A chart was made graphing these two correlation’s, time vs.color and intensity of color vs. time. ( See chart one for results). Time( 3:35). When the “system” was tapped against a pencil a low octave sound was produced. If the “system” was shaken then and pencil was tapped against it, the sound became a higher pitch. This experiment was done three times to make sure there was a difference in sound every time. The next thing that was done to the “system” was that it was cooled in an ice bath. It stayed submerged in the cold water for five minutes. When observing the test tube there was a small ring of blue color around the meniscus. The “system” itself became a lighter color from when it was first placed in the ice bath. Small particles were collected at the bottom. (3:46) When it was taken out the test tube was shaken again to check the color change vs. time. It appeared that it took longer for the blue to disappear now that it was cold. The color intensity was greater than before every time the shakes became stronger (See chart two for results). A hot plate was turned on and a beaker of water was placed on top to boil. The dial had been placed on four. The “system” was placed inside using test tube tongs. It was kept inside for five minutes. (4:05) The liquid changed to a rusty orange, and was a dark red at the meniscus. When the “system” cooled, it was shaken to test any change in appearance. The color remained constant when shaken. Next, it was time to open the system. The cap was removed and dried, then set on a paper towel. The top of the test tube was dried so that the “system” would not get on the observer. It appeared to have an alcohol smell to it. The cap was placed back on and then the test tube was shaken again. Nothing seemed to happen. Then the “system” was doubled in size, using a graduated cylinder to measure with. It was heated and placed in an ice bath again for five minutes and still no change in color. Conclusion: From this experiment I think that the bubbles in the test tube had something to do with a chemical reaction within the “system” Every time the bubbles came to the surface they busted and released some sort of substance that mixed with the “system”, creating a blue chemical reaction. There must have been two substances in the test tube, and when shaken would mix to form this color change. If the test tube was shaken for a long period of time more bubbles would be created and thus increasing the color intensity. The charts relate to my hypothesis. The reason that it could be the bubbles and not the cap being part of this reaction is that when the test tube was flipped upside down and shaken, the intensity of the color still originated from the top and gradually became lighter. This again relates to the hypothesis made. When the “system” was placed in cold water and than shaken the color took longer to disappear. Coldness on it could prolong the bubbles from bursting making it able for the blueness to remain longer. When the “system” was heated it changed complete color, from a pale yellow to a rust colored orange. A chemical reaction could have occurred to permanently alter the two substances in the “system”. The addition of water did not seem to change the “system.” When it was doubled nothing changed in color. Another hypothesis that I came up with is that oxygen had something to do with the chemical reaction in the “system”. If the it is exposed oxygen got change the liquids if it is mixed. It could catalyze a reaction in the “system”. To test this the “system” must be placed into a vacuum so that no oxygen would be inside. Experiments could be made and compared with a “system” that had be exposed to oxygen.