For the past week, in science class, we did several labs involving matter. We observed the states of matter and other aspects of matter. The main purpose of the labs was to understand the distance between chemical changes and physical changes. Through the duration of the week, other knowledge was also compiled.
The first two labs were in the same context because both involved candles. The first was quite basic. Notes were taken on the physical properties of a candle. However, no chemical properties were noted because one cannot observe matter’s chemical composure unless it is manipulated. Once the candle was lit, observations on chemical and physical properties were recorded. Physical changes were first written down. These would include that it was melting, smooth, and shiny. Now that it was lit, chemical changes included things such as the fact that it was burning. The evidence of this was shown in the flame and smoke. In addition, this lab was a source of knowledge involving combustion. Combustion is the act or process of burning. Thus combustion occurred when the candle was lit. People see combustion on a daily basis without even acknowledging it. When someone lights a candle in their kitchen or lights a birthday candle, one could say that they are performing a science experiment. This could be useful when forming hypotheses regarding combustion and burning.
The second part of this lab involved candle but had a different purpose and procedure. A candle was set aflame first and then a mixture of vinegar and baking soda was created. This formed a gas known as carbon dioxide. This gas was poured over the candle and caused it to blow out. The carbon dioxide surrounded the air around the flame, which needs oxygen to survive, and removed the oxygen, putting out the flame. A physical change occurred when the candle was lit and it was put to a stop when the fire went out. Insight into the life and death of flames was provided and can be used on a regular basis. The air we blow out of our mouths is carbon. So, every time we blow out a candle with our mouths we are performing this experience in a different way. An understanding of the science behind blowing out candles was developed.
In the following lab, physical and chemical changes of a marshmallow were performed and identified. After notes were initially taken on the description of the marshmallow, it was ripped in half. This was a physical change because it only affected its form, not its composition. Next, a bite was taken from the marshmallow. This was done to have an initial taste. After another marshmallow was placed on a skewer, it was held over a Bunsen burner until it was burnt. The blackened part of the marshmallow was tasted. The taste of the marshmallow changed drastically. For one, instead of being sweet, chewy, and powder-like, it was smoky, creamy, and crispy. Both physical and chemical changes had taken place. A chemical change happened when the marshmallow was burnt and when the inside melted a physical change occurred. After completing the procedure, it is now clear to me that whenever we roast marshmallows, we are executing a scientific procedure involving physical and chemical changes.
The final lab involved sugar cubes. Two sugar cubes were first taken and crushed into a powder with a mortar and pestle. The sugar had been grinded and it underwent a physical change. It was then poured into a glass of water and stirred. The sugar was no longer visible and had dissolved, going through a physical change. However, the sugar was still present because the water tasted sweet. Next, two different sugar cubes were put in a test tube and were held over the Bunsen burner. Observing the contents of the test tube, it was noticed that the sugar was burning and turning black. Smoke started coming out of the tube and black crystals were formed inside the test tube. Once the test tube was taken off the flame, many other changes were noticed. The sugar was now burnt, black, and crystallized. In fact, it wasn’t sugar anymore. Once sugar underwent the chemical change of being burnt, a new substance was formed inside the test tube. This lab conveyed the significance of chemical change in such a simple substance as sugar.
Clearly, physical and chemical changes of matter can be observed in numerous ways. The above labs utilized burning and flames to entice the students to want to learn about matter, chemical changes, physical changes, and other related topics. To conclude, forming an understanding of substances and chemical changes can not only help in an experiment in a laboratory but can also add to people’s knowledge of reactions that happen throughout their lives on a daily basis.
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