The National Park Service offers hundreds of free, standards-aligned lesson plans, many of which can easily be used in classrooms anywhere. A great example is this geology lesson plan provided by Craters of the Moon National Monument & Preserve. Written for elementary students in grades three to five, this lesson uses two interactive activities to teach students about the different layers that make up the Earth's structure and aims to convey the idea that the Earth is dynamic rather than static. In the first activity, the class (with direction from their teacher) creates a human model of the Earth in which students role-play the Earth's layers with movements appropriate to each part. For example, depending on the size of the class, one or two students would play the inner core, three or four would play the outer core, and so on through the deep mantle, the aesthenosphere, and the lithosphere. In the second activity, students work in small groups to build a cross-sectional model of Earth's layers using inexpensive household supplies. Together, these engaging activities are estimated to take about 90 minutes of class time. A vocabulary list, background information, and links to additional resources are also included.