Observations and the Scientific Method
Third grade Chemistry lesson
Liaison: A.S. Chang
Date: 2/28/97
Group Members: Scott Damrauer, Greg Sawicki
School: Fletcher
Teacher: Ms. Valentine
Materials:
Dry Ice
Water
cups
Iodine Clock reaction materials:
Potassium Persulfate, KI, Na2SO4, starch
Procedure:
This was our first time with the class, so we decided to do all the demos ourselves and wait until we speak with the teacher to plan the overall unit for the semester. We began the class by introducing ourselves and asking the kids to each say their name and favorite cartoon character. We then went through the parts of an experiment. We asked the class what they knew about experiments. They were able to say that experiments test things, invent things, and discover things. On the board, we wrote the steps of the scientific method.
First is the question, then hypothesis or educated guess, then observations and data, and finally conclusions.
For the rest of the time we focused on observations. One of the kids gave us the working definition: to observe is to look, feel, taste, and smell. We had to remind the class that in science, you should not taste your experiments, but the other parts were all important.
The first demonstration we did was putting dry ice in water. The kids really like this since it gives off a lot of smoke. We showed how the frozen CO2 turns immediately into a gas (the smoke) and answered questions from the class about what they were observing.
The second demo was the iodine clock reaction. If you mix the three chemicals together and then add a few drops of starch, the solution will turn from clear to purple-black. The time of the reaction depends on the ratio of starting materials. We tried different amounts since we didn't have the recipe, and some worked faster than others. The class was intrigued by the color changes and asked a lot of important questions.
Evaluation:
Comments:
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