|Heating baking soda using a gas collection apparatus.|
I found my inspiration for this experiment from the IPS book (Introductory Physical Science - 8th edition by Uri Haber-Schaim). The opening experiment in this inquiry-based physical science program is to heat baking soda. As I read through the teachers guide for more details, I came across this statement: "The original mass of baking soda doesn't matter, more baking soda will increase the volume of gas produced." That's when I decided to make this into a controlled experiment with an independent variable and dependent variable. This simple experiment can be easily manipulated to collect enough data to explore the relationship between the mass of baking soda used and the volume of gas produced.
On the first day of experiment, I taught all the students how to light and extinguish the Bunsen burner.
|Gas bubbles can be seen in the inverted bottle.|
|Each group used a different mass of baking soda in the second trial.|
I really enjoyed starting the year with this lab because it has so many introductory concepts all wrapped into one. The kids learned how to light the Bunsen burner, they designed and implemented a controlled experiment, they leaned how to measure the mass of a powder and the volume of a gas, they assembled apparatus to collect a gas, they plotted a graph of their data, and answered an experimental question. I call this a home run in the first week of chemistry class.
|A graph of my class data, not bad for the first experiment of the year.|