This Exciting Week: States of Matter+Fire=Awesome!

             This week in science class we learned about states of matter by doing oodles of fun experiments. First, we made slime by mixing glue with water and borax, a cleaning liquid. It was very fun, and i learned how to measure correctly AND how to basically knead in the food coloring into my slime. The slime was a colloid, which is a mix between a liquid and a solid. In this substance, the water molecules are held up by the borax and glue molecules, so it becomes a colloid. That was a chemical change because the molecules rearranged into a new compound. The experiment we did after that was carbon vs. candle. First, we lit a small candle and watched it burn. That was our control in our experiment. Next, we lit the big candle. Right after that we mixed some baking soda and vinegar together. I learned not to pour too much, because my group did and it overflowed right over the cup! (this could be bad if i am ever cooking or doing a more dangerous lab) We cleaned it up, then we did it correctly. We held up the cup full of baking soda and vinegar up to the candle- and the flame went out! This is because the baking soda and vinegar combine to make carbon dioxide. This is a chemical change, because the vinegar and baking soda combine to make a new substance, which is carbon dioxide. Fire needs oxygen, and when you put carbon dioxide up to the flame, it smothers the oxygen around it and causes it to extinguish. Now i understand how a fire extinguisher works! The third lab we did that week was roasting marshmallows. Yes, that sounds like something you do at a camp, not in a lab, but it has surprising science background. When i put my marshmallow up to the flame, the fire heated up the sugar in the marshmallows, causing it to caramelize, and then when it got even hotter, char. When i tasted the blackened part of the marshmallow, it tasted bitter and burnt, like charcoal. I did not like that taste. This taught me not to overcook food, or else it will taste like the burnt marshmellow. This is a chemical change called oxidation. This is when some pieces of the marshmallow burn up and are sent into the air. The blackened parts are in the process of burning. The last lab we did this week was burning pure sugar. We took a sugar cube and we crushed it, making that a physical change. It changed form but not its molecular structure. Next, we put sugar in water, and swirled it in. That is a physical change because if you evaporate the water, then the sugar would still be left. The sugar is still unchanged, it is just distributed around the water. Finally, we took a sugar cube, broke it up, placed it in a test tube and put it over the bunsen burner. It was quick to burn, and it made a black substance that looked an awful lot like tar. It immediately hardened. This is a chemical change because sugar is a substance made of carbon and water. When you burn it, the water evaporates leaving only the carbon behind. This helps me learn about sugar, and i can learn why and how it heats up. It also helps me learn how fire can change a substance.