Students discover how to "read" tree rings to determine the date of a volcanic eruption and the effects an eruption has on plant growth. After a lecture/demo, students utilize a worksheet imbedded in this plan to date an eruption.

Fourth graders sort seeds and predict what conditions are needed for them to germinate. They keep the seeds moist, observe and measure their growth and graph the results. As the seeds start to grow students compare and contrast the each...