In Chemical Mystery #7, a can of Coca-Cola was observed to sink in one container of water and yet float in another! This trick made use of the fact that the density of water changes with temperature.
Q: Does an unopened can of soda pop float or sink in water?
A: It depends!
See if you can figure out what is happening in this twist on the classic floating-and-sinking soda can experiment.
Throughout the last ten years teaching both chemistry and Advanced Placement Chemistry I have realized that the concept of equilibrium does not receive enough attention in my first-year chemistry course. Sure, the concept of equilibrium is a topic mentioned and identified throughout the course however the dialogue in regards to conditions that would shift the chemical system is minimal at best.
Inspired by Tom Kuntzleman*, I started using mysteries in my chemistry curriculum this past year. The first mystery I shared with my students was burning water. While my magician skills aren't perfect, I was able to get the students asking questions and proposing hypotheses. For my IB students, it really allowed me to delve into a number of topics (e.g. combustion, intermolecular forces, polarity, density). And thus an idea was born: Using one mystery per topic. In this blog post I'll discuss my beginning effort to find or develop a mystery for each topic within the IB Chemistry curriculum.
Solution to Chemical Mystery #6 is presented. Also, concepts related to the chemical can crush demo are briefly discussed.
Can you figure out how this experiment works?
Flinn Scientific has a great elearning video series. Many of the videos have master teachers demonstrating some great labs and techniques that they do in the classroom.
This year in the midwest United States, winter has been a fickle friend. I haven’t seen the same amount of snow or ice as in recent years, but I still made sure I was prepared for it at our home. I went to my local big box hardware store in December and contemplated buying rock salt (NaCl), and NaCl/calcium chloride mixture, or just calcium chloride. Growing up my dad had switched entirely to calcium chloride because it was less damaging to the brick pavers leading to our porch and backyard. In fact, calcium chloride is generally much safer toward plants and soil than NaCl. Even though calcium chloride is much more expensive than rock salt (it was about twice the cost for 10 pounds more), that what’s I chose. Why?
This past summer our conversations turned to, “How can we improve our instruction to try and prevent the initial misunderstanding?” We had all read Dorothy Gabel’s article Improving Teaching and Learning Through Chemistry Education Research: A Look to the Future. We were intrigued by the author's description of the three fold system of representing concepts in chemistry.
Chemical bonding can be a confusing topic for teachers and students. Chad Husting shares his struggle.