This activity engages learners to make a model of sediment cores using different kinds of glass beads and sand. They learn how to examine the types, numbers, and conditions of diatom skeletons in the model sediment cores and tell something about the hypothetical paleoclimate that existed when they were deposited. The students get to be climate detectives.

In this activity, students make a model sea floor sediment core using two types of buttons to represent fossil diatoms. They then compare the numbers of diatom fossils in the sediment at different depths to determine whether the seas were free of ice while the diatoms were alive.

This narrated slide show gives a brief overview of coral biology and how coral reefs are in danger from pollution, ocean temperature change, ocean acidification, and climate change. In addition, scientists discuss how taking cores from corals yields information on past changes in ocean temperature.