In this activity, students will learn how radar altimetry is used to measure sea surface height, and determine the direction and speed of ocean surface currents from TOPEX/Poseidon altimetry data. Procedures and materials are provided. Full description.

This document provides a brief description of the major currents and general circulation patterns of the world's oceans. Links to animations showing satellite imagery of ocean-surface topography and temperature are included. Links to references are embedded in the text. Full description.

This is an introduction to the concept of seafloor spreading proposed by Harry Hess in the early 1960's. This site offers multiple links to further examine this geologic hypothesis. Full description.

This lesson focuses on the effects of volcanic eruptions on atmospheric chemistry. Students will use the internet to acquire data, analyze it graphically, and perform further analyses on recent eruptions and on hypothetical eruptions of their own. Procedures, standards, and links to the necessary materials are provided. Full description.

This document briefly discusses the two models most favored for the formation of Earth's atmosphere and compares the present-day atmosphere to the early oxygen-lacking atmosphere. Links to related topics are included. Full description.

This document presents a number of theories, both plausible and implausible or even humorous, for the extinction of the dinosaurs. Links to a glossary are embedded in the text. A reading list and links to related sites are also provided. Full description.

This online calculator helps students understand the classic analogy of relating the geologic time scale to a yard stick. It will help reinforce the concept of the briefness of human history relative to the age of the Earth. Full description.

Students can put their weights into this calculation tool and see how much more or less they would weigh on the other planets, moons, our sun, and other types of stars. The tool is accompanied by discussions of mass, weight, gravity , and distance. Clicking on the images of the planets links the user to additional information for each one. Full description.

This news article examines evidence that parts of the Antarctic ice sheet have undergone episodes of instability that appear to correspond with periods of unusually warm temperatures in the Northern Hemisphere during the last ice age. Full description.

This article describes how students in Alaska are helping scientists study earthquake hazards by conducting global positioning system (GPS) measurements in order to track crustal movements in the Earth's crust. It points out the importance for Alaskan inhabitants of understanding the hazards and physical processes associated with earthquakes, describes how the students located and installed a network ... Full description.