Give our ocean voyagers the "Hydrothermal Vent Challenge!" It is a worksheet that guides them through an exploration of hydrothermal vents and the chemical reactions that occur when lava meets seawater. Using a collection of websites, they gather the answers to questions and then participate in a discussion of their newly-found knolwedge. Use this in high-school chemistry when studying chemical reactions, or in a geography class when studying plate tectonics.