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Welcome to the Chemical Education Xchange (ChemEd X)! We hope to strengthen the community of chemistry educators by providing learning resources and forums for discussion and collaboration right here at this site. Take a look, and join in.
Each year we do an activity that involves Archimedes principle. You might wonder...why do this in chemistry? Leading up to the activity, students do a series of labs and activities that involve measuring, accuracy, precision, significant numbers and density. The culminating guided inquiry activity takes place by which students take an object, find the volume in multiple fluids and find the mass in multiple fluids. An examination of class data starts to show that the volume of a solid does not change in fluids but the mass in air and the mass in different fluids are different. They also use the density of the fluid and the volume of the fluid displaced by the submerged mass to find the mass of the fluid displaced. The hope is to guide student's thinking to help them understand that the apparent loss of mass, or the buoyant force of the fluid against the mass is the same as the mass of the fluid displaced. In theory, this should be a great lab. The reality is that the instruments we have are less then ideal, it is tough to guide students with bad data and there are many connections that need to be made.
There has been considerable discussion lately of standard based teaching. Essentially, a teacher has a set of standards and they teach to these standards. The idea is that instead of saying "Hey, you got a C on this test, time to move on..." a teacher would say "This is the standard...you can exceed it, meet it or you can approach it...the goal is to meet or exceed the standard and if you do not, keep trying." Here is an example...we were covering gas laws in my class. I asked seven questions about conceptual ideas concerning gas laws. Students manipulated an HTML 5 site in which they could watch models of gases and change the volume temperature and pressure. Students then answered the questions on a bubble sheet that I simply placed in front of my web cam. It was instantly graded. The grade was not a letter grade...it was a sign that said that they were getting close to the standard or they met or exceeded the standard...no grades were assigned.
I started teaching in a chronological order when I began using Modeling Instruction in my classroom. During the second year of "walking in the footprints of the scientists that came before us", I wanted my students to see where they were walking and a colleague and I came up with the idea of making footprints for each of those scientists and posting them on a timeline.
ChemEd X recently made a Call for Contributions soliciting input regarding the big ideas being put forth by organizations like AP. The first thing that came to mind was a lab I modified that is centered around making connections between topics. Admittedly, this lab is not a "big idea" per se. Rather, it's the big idea that students should be able to make connections between topics we study to solve problems. So in this blog post, I would like to share a lab activity that relies on these connections - between stoichiometry, esterification, equilibrium, kinetics, titrations and uncertainty of calculations. I will also share the resources I have created to support my students through the process of working through these calculations.
Three class periods
Day 1: setup of equilibrium mixture; roughly 30 minutes
Day 2: titration of equilibrium mixture (approximately 1 week after Day 1); roughly 60 minutes
Day 3: calculations; variable time required - typically 30-90 minutes depending on the student group
How do teachers encourage building individual lab skills in classes of over 30 students where labs are done in groups of five or six students? My science department collaborates daily, and we have been discussing this concern for a few years now. Many trials and errors have occurred.
This school year my district is launching a 1:1 Chromebook initiative. 6th and 9th graders will receive their Chromebooks next semester as part of the rollout. In the meantime, I continue to have access to my Chromebook cart from the Blending Learning pilot I participated in last school year. My goal is to incorporate even more tech use when appropriate; so far, I have increased Chromebook use in my classroom for things like warm up questions, EdPuzzles, and quizzes. My experience with quizzes has been especially interesting.
“You sank my battleship!” Do you remember this line from a classic commercial featuring the board game Battleship? It sat in my family’s game closet when I was a kid, but it’s popping up again recently, with chemistry twists.
