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.
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.
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.
College Board offers an excellent online resource for teachers and students. It's not free, but my school district pays the bill. AP Insight provides curriculum outlines, teaching ideas and resources, student handouts, and digitally-graded assessments. I have elected to begin using the resources in first semester honors chemistry.
Here is what I told my students as we were studying gas laws. I have a bag of potato chips at see level and then I go to Denver where the pressure is less? What happens? Draw and build a model on your whiteboard.
Is it possible to use materials found in high school chemistry labs to extract and subsequently detect cocaine on dollar bills? Let me know what you think after reading this blog post!
In the article “Reactions Catalyzed by an Assault on a Favorite Principle”1, Emeric Schultz (who incidentally taught me General Chemistry, was my undergraduate advisor, and is now a dear friend and colleague) argues the following:
“Although I have read and heard about ‘big ideas’ in chemistry, I have never seen a commensurate effort to work toward a high school chemistry program that starts from…big ideas and works down.”