Chemical and Physical Changes and the Law of Conservation of Mass
The lesson began with students getting out of their chairs to model physically the behavior of molecules in the different phases within a taped off portion of the floor. I was actually really pleased with how well the students were able to act out the different phases, although they did resist the activity a little. Many students seemed a little uncomfortable getting out of their chairs and doing things other than taking notes or working on practice problems. A few misconceptions (or maybe just poor acting) were occasionally seen in the different periods. The "gas particles" forgot to move in a mock random way and were carefully avoiding each other. The "liquid particles" tended to fill the entire area instead of staying nearer each other and near the bottom of the "container." The solid particles didn't move at all and had to be encouraged a little to show some vibration.
The part that I really wanted to get to was asking "the particles" to model what happened when they got warmer/cooler and at higher/lower pressure. Students struggled with this a lot more but I felt it really helped some of them engage in higher level thinking.
After this we moved into a quick discussion about the words used to describe the changes from phase to phase. The diagram in the Prezi facilitated this discussion and students were encouraged to jot down their own version of the presentation. We also had a quick interlude discussion with the first penguin about the differences between the words gas and vapor. At the end of the discussion of the names of the phase changes students were asked to explain to their partners why the phase changes occurred in a think/pair/share.
We then reviewed the definitions of physical properties and introduced the new concept of physical change. The same thing was done for chemical properties and chemical change. During the review and extension of these terms students were asked to collaborate in small groups to generate ideas and answers before being asked to risk their answer in front of the whole class.
We then transitioned into a lab activity where students were encouraged to prove or disprove the law of conservation of mass. The name of the law was not introduced at this time to avoid influencing the student's process. Students were told that the y would have a few chemicals that do react in order to test their hypothesis. After giving students time to discuss their ideas and questions they were allowed to perform the experiment. A data table at the front of the class was used to record their results. After the experiment we talked about the law of conservation of mass and about how the experiment could be improved to do a better job of proving our hypothesis. We ended with a simple chemical equation and practice problem to reinforce the law of conservation of mass.