The discussion that follows this investigation helps the teacher assess students' knowledge of solids, liquids, and gases and some of the changes that can take place when solids and liquids are mixed. Finally, students prepare for Lesson 2 by watching their teacher fill ice cube trays with water. The trays are put in a freezer for the next lesson. In Lessons 2 and 3, students investigate how water changes state. They begin by describing how the water in the ice cube trays has turned to ice.
Students then design a method to melt the ice in the quickest time possible.
At the close of the lesson, they place the melted ice in a petri dish. Over the next few days they observe changes in the water as it evaporates over time. In Lesson 3, students discuss these changes caused by evaporation and then set up an investigation in which they observe condensate forming inside the cover of a cup of warm water. Lesson 4 begins a series of lessons in which students investigate changes involving mixtures. Using a sieve, students then discover that they can separate their mixture again into its individual parts, and they develop a basis for understanding the mixtures they create in later lessons.