Water impurities affecting salt crystal growth Chemistry Experimental Investigation ___________________________________________Signature of Sponsoring Teacher ___________________________________________Signature of School Science Fair Coordinator TeacherAdam Federspiel640 W. Scott St.Chicago, IL 60610Grade 8 Table of ContentsAcknowledgments                                                                                       Page 3Purpose and Hypothesis                                                                              Page 4Background Research                                                                                  Page 5Materials and Procedure                                                                             Page 6Results                                                                                                            Page 7Conclusion, Reflection, Application                                                          Page 8Reference List                                                                                                 Page 9 AcknowledgmentsI would like to thank my parents for getting the materials I needed for my project, and for helping me with my experiment. My dad was the one who gave me the idea for this experiment. He also helped me set up the project. Without him, I probably would have failed this class. Purpose and HypothesisThe purpose of my experiment is to test if water impurities such as sugar or cornstarch affect how salt crystals grow in water. Salt crystals are grown when salt is mixed with hot water. The salt is dissolved and makes the water into a solution. My hypothesis for my project was that the impurities would affect how the crystals grew.For the experiment, we used ten jars. Nine of them have have water impurities, but one of them doesn’t. That one is the controlled variable. The water impurities we are using are sugar, rubbing alcohol, and cornstarch. We made 3 sets of jars, one for each type of water impurity. I used 3 jars for each set. One jar in the each set will have one tablespoon of the impurity, one jar will have two teaspoons, and one jar will have three. The one jar with no impurities is the controlled variable. The independent variable is the amount of crystals grown, and how much impurities have been added into them. The dependent variable is the size of the crystals. Review of LiteratureMost people know that Salt is a compound of sodium and chlorine. Salt crystals are formed when sodium and chlorine bond together via a shared electron and these sodium and chlorine molecules bond with other sodium and chlorine molecules. They are first single molecules, and then as the molecules bond together, crystals are formed. Every molecule will form the same shape crystal each time it forms. The crystal shape for salt is a cube. Water dissolves the connection between the sodium and chlorine atoms, but when the water evaporates, the connection can re-establish itself.  Materials and ProcedureMaterials: 10 clean jarsWater60 tbs of salt. 6 teaspoons of sugar6 teaspoons of rubbing alcohol6 teaspoons of cornstarchString10 Pencils.Procedure: Step 1: Start setting up experiment by pouring in half a cup of water into a pan. Step 2: Heat the pan of water.Step 3: When the water starts to make small bubbles, mix in one fourth of a cup of salt and begin stirring it. Stir it until no more salt grains are visible. Step 4: When no more salt grains are visible, pour in a spoonful of salt. Step 5: Keep adding more spoonfuls of salt and stir them until you see salt grains that won’t dissolve when you stir.Step 6: Pour the solution into 1 clean, empty jar.Step 7: Tie a string around a pencil, and then balance the pencil on top of the jar.Step 8: Wait for the salt crystals to grow. This can take a few hours to a few days.Step 9: Measure the crystals and record the data.Step 10: Repeat steps 1-8, but this time, use 9 empty jars add water impurities into the solutions.Step 11: Measure the crystals and record the data. ResultsWeight of CrystalsImpuritiesCornstarchSugarRubbing Alcohol1 teaspoon1 gram1.1 grams1.1 grams2 teaspoons1.1 grams1 gram0.9 grams3 teaspoons0.8 grams1.1 grams0.7 gramsControl crystal: The control crystal was the crystal I made without any impurities. It’s weight was 1.7 grams. Conclusion, Reflection, and ApplicationMy science fair project is about making salt crystals. I wanted to find out if water impurities affected how they grew. I hypothesized that they would interfere with the growth. I tested it by making 10 different crystals, 9 with impurities and 1 without. The one without impurities was the controlled variable. I noticed the results varied, but the crystal without impurities was the biggest one. My hypothesis was proven correct, because all the crystals with impurities were lighter. Therefore, the impurities slowed the growth of the crystals. I learned that water impurities such as sugar, cornstarch, and rubbing alcohol can affect salt crystal growth.I feel like my tests were somewhat fair. I’m unsure if my results were accurate, because instead of using actual tablespoons and teaspoons. If I could change anything about my experiment, I would give my crystals more time to grow. I would probably use more accurate measurements, but I would keep my procedure the same. However, I am curious about how people first discovered salt, and how to make it.This experiment can be used in a real life situation, because some people like growing crystals for fun, others do it for school, and others do it for a living. My experiment connects to our lives, because we put salt on a lot of different foods. Salt crystals are just bigger versions of the salt grains. My experiment explains how things work the way they do, because it shows how salt is made. Salt is made when sodium and chlorine atoms bond, creating sodium chloride, also known as salt. Reference Listwww.saltassociation.co.ukwww.wikihow.comhttps://learning-center.homesciencetools.comhttps://www.education.com/science-fair/https://www.sciencebuddies.org/

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