## Unit 2: Energy and States of Matter (Duration: ~ 3 weeks, or 13 class meetings)

This unit began relatively normally, with diffusion demos and storyboards. We watched the Eureka! videos, and we discussed measuring temperature, and how to represent cold and hot particles in motion. We had a great discussion on our particle representations, when forced to remove all words from our whiteboards.

After a discussion of thermal expansion of liquids and solids, rather than moving on to pressure and gases, we went right to heat and temperature. Continuing with the Icy Hot Lab, we introduced energy bar charts to describe the changes qualitatively.

For time reasons, we did not complete the Lauric acid activity, but one valuable addition was a worksheet for students to practice drawing temperature-time graphs for substances other than water. We finished with quantitative calculations for phase and temperature changes.

This change in sequence seemed natural. I will definitely repeat next year.

I have been teaching modeling at the college for >4 years. However, I am trying to implement it in the HS classroom and am having trouble with student compliance. They truly love the hands-on activities and laboratory work and are fully engaged but I am having trouble with engagement when it they have to dig in and do problem solving that requires deeper thinking and more advanced mathematical application. They shut down instead of embracing the challenge. How do you keep the students working while you are working with different groups in the classroom?

Why did you decide to teach heat and temperature before pressure and gas instead of after?