We did four labs in science. These labs were very similar and their goal was to teach us more about physical and chemical changes as well as describe the physical and chemical properties of a substance. The four labs we did were; “Observing Changes in Matter,” “Observing a Candle,” “Pouring a Gas,” and “Marshmallow Fun.” To begin with, “Observing Change in Matter” showed many examples of physical and chemical changes. First, we observed the physical properties of the sugar cube. The sugar cube was; small, white, cube shaped, hard, bumpy, and it tasted sweet. Next, we grinded the sugar cube with the pestle and that was a physical change. It was a physical change because the appearance changed of the substance but its composition or identity did not change. Another physical change that occurred in this lab was that we mixed the grinded sugar with water. This was a physical change. When we lit the sugar over the Bunsen burner, the sugar was mixed into water and carbon. The water evaporated into the air, and a new substance was left, carbon. This was an example of chemical change. A chemical change is when a substance is changed into one or more new substances. Next, “Observing a Candle,” lab had a chemical change in it; we also had to observe the physical and chemical properties. The chemical change that happened in this lab was that the candle burned, which is an example of chemical change. Two physical properties displayed after the candle was lit were that the candle melted and its stem grew longer. A chemical property that was shown after the candle was lit was that the candle burned. Next, “Pouring a Gas,” lab also displayed a chemical change. When my group and I mixed vinegar and baking soda together we formed a new substance call carbon dioxide. This was one of the chemical changes that occurred. Next, we poured the carbon dioxide over the lit candle. The flames went out because carbon dioxide does not support burning. When the flames were blown out they were turned into gas. This happened because the oxygen was diminished so the flame couldn’t survive. This was another chemical change. Lastly “Marshmallow Fun,” lab displayed both a chemical and physical change. The first part of the lab was a physical change. The lab said to rip our small marshmallow in half. This was a physical change because the appearance of the substance changed but its identity did not change. When the marshmallow was ripped it was still a marshmallow but it just looked different, it was in two pieces rather than one. Next, when we burned the marshmallow over the Bunsen burner that was an example of a chemical change. This was an example of chemical change because a char was formed on the marshmallow. The physical properties also changed because the marshmallow tasted sweet and burnt, it was mushy, charred and looked black. Through all these labs I have learned many new things. First, I have learned how to differentiate between a physical and a chemical change. A physical change is when the appearance of a substance changes but its identity does not change. A chemical change occurs when a substance is changed into one or more new substances. I also learned that physical and chemical changes can occur every day. For example, a physical change is cutting paper in to two halves and an example of chemical change is roasting a marshmallow. Next, I learned how to describe the physical and chemical properties of a substance. As you can see, I have learned a lot from these labs, and they will help me in the future when I become something to help this world.
