I usually start of the school year with a measuring activity. This year, I used Tom Kuntzleman's Mentos and Diet Coke experiment and had students use the data to do some graphing and analysis. This was a nice lead into our gas unit. I also made my own syphon coffee maker to demonstrate for my students.
I added an extra step including a follow up Claim, Evidence & Reasoning activity to the familiar whoosh bottle activity.
A favorite demonstration is to boil water by lowering the pressure in a bell jar using a vacuum pump. Unfortunately, purchasing a bell jar, vacuum plate, and vacuum pump can run upwards of $1,000 which poses a hardship for many teachers. Here are two simple and inexpensive demonstrations of phase equilibrium and vapor pressure.
If you want to lose weight, you have to burn calories. Anyone who has gone on a diet knows this. But when someone loses weight, have you ever wondered where the lost mass goes?
Based on some interactions here on ChemEd X and Twitter, I have been looking for ways to have students generate more questions, ideas, and investigation methods. (See a list of relevant links below.) Some of this is inspired by Argument Driven Inquiry, while some of it is simply my own quest to move further away from being the sole source of information in the class. In this blog post, I would like to talk about how I addressed gas laws using Atomsmith Classroom Online as an investigative tool in place of lab work I did previously using the Vernier gas pressure sensor.
Recently, my district made a commitment to helping its teachers reflect and rethink their grading and assessment practices. One of the phrases I kept hearing throughout our staff professional development sessions was authentic assessment. I understood (and agreed with) the basic premise—create more opportunities for students to perform tasks that demonstrate meaningful application of essential knowledge and skills. Doing so involves going beyond, or even potentially replacing, traditional summative assessments at the end of each unit.
Students can sometimes struggle to grasp gas behavior, as it’s much harder to visualize gases rather than readily available solutions, solids, or mixtures. Indeed, for many labs, if gas is a product, we’re often relegated to using balloons or gas columns to capture and measure the gases produced by reactions, which can be tricky or expensive. So this year, I tried something a little different when starting my intro chemistry students’ gas laws unit, and was very happy with the results.
It was close to the end of the semester and we were covering gas laws. Students were stressed over the idea of finals, final projects due, tests before finals and the holidays. Since we were finishing up the topic and it was important to end with one last assessment and/or lab but the timing was not good and the stress level for everyone was at an all time high. A different course of action was needed.
The solution to Chemical Mystery #9: Liquid Nitrogen vs. Dry Ice is presented. Why does liquid nitrogen launch the bucket so much higher than dry ice and water?
A 2L soda pop bottle is filled about one-third full with either liquid nitrogen or solid carbon dioxide (dry ice) and water. The bottle is sealed and a plastic bucket is placed on top. Do you think the liquid nitrogen or dry ice and water will make the bucket go higher? Can you explain the results using chemistry?