Have you ever cooked a marshmallow in a microwave? In case you are not familiar with this experiment, when a marshmallow is heated in a microwave, gases trapped in the marshmallow expand and escape. When the gas molecules escape from the marshmallow, they push against the marshmallow, causing it to expand. To see this experiment, play the video below.
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Moles, mole ratios and stoichiometry have been frustrating topics for many of my chemistry students. The MOLE and Avogadro’s number get tangled up in other Chemistry jargon and students have stared at me like I am speaking another language. I have been around long enough to know this is a problem that many of us have faced. I have tried many ideas that have helped and I want to share a few.
Sunday, July 28 to Thursday, August 1, 2013, the largest conference in North America focused on teaching high school and introductory chemistry will be hosted by the University of Waterloo, Waterloo, ON Canada.
Allow me to introduce myself, my name is Doug Ragan and I have been a high school chemistry teacher for fourteen years. Three years ago, I was approached by my high school principal and the conversation went like this,
Principal: "You are one lucky guy."
Me: "Really, why?"
Samuel Arbesman, a mathematician and network scientist, uses the idea a half-life as an analogy for the changes in human knowledge that science brings. He discusses both the changing rate at which new science is done and the speed at which old results are replaced by newer ones. The analogy is far from perfect, but it emphasizes some critically important aspects of the processes of science.
Whenever possible, I try to begin a topic with something my students are familar with. For the introduction of Percent Composition in my general chemistry course, I brought in bags of Oreo cookies. Seeing the bags upon entering class was a great attention getter. If you are looking for ways to add more inquiry to your chemistry course, this a an example of how can experiment with giving up a little control. Try it and see how it goes.
I wrote the following directions on the board: Obtain an Oreo. The cookie is made up of WAFER and CREAMY FILLING. Using a balance, a plastic knife and a napkin (to keep the cookie from directly touching the balance), calculate the percent of the cookie that is made up of each part. You have 10 minutes to complete and be ready to explain the process and your answer.
Celebrating 90 Years as the Premier Chemical Education Journal
The January 2013 issue marks the start of the 90th volume of the Journal of Chemical Education. This latest issue plus the content of all past volumes, 1 through 89, are available at http://pubs.acs.org/jchemeduc.