For the first lesson of Chapter 11, students worked with dry ice and watched a couple of teacher demonstrations involving dry ice. To begin class, students quickly assembled into groups of four and transferred a small amount of dry ice (provided in a styrofoam cup) into a deflated plastic bag which they sealed closed. Students measured and recorded the mass of the dry ice added to the bag (by subtracting the mass of the empty cup from the mass of the cup with dry ice). Students then observed the plastic bag throughout the remainder of the class period.

In the interim, students hypothesized about what they might observe when water ice and dry ice were heated on a hot plate, and also what would happen when water and dry ice were added to liquid water or vegetable oil. They then observed the outcomes and recorded their observations on the Lesson 56 Worksheet. Students also recorded the definitions of **sublimation** and **evaporation**, both of which are included in the Lesson 56 PowerPoint.

Students also received back their graded Chapter 10 quizzes. Notes from the short answer section are pictured below, along with calculations of how to measure the volume of carbon dioxide gas inflating the plastic bags from the lesson. Students may replace their short answer scores from the quiz by substituting new numerical values for the problems and solving the problems with the new numbers.