The Significant Earthquake Database is a global digital database containing information on more than 5,000 destructive earthquakes from 2150 B.C. to the present. Users can access these data in two different ways: via a two-volume CD collection, or on-line. Users searching on-line can query the database via the following parameters: the year of the event, geographical coordinates (latitude and longitude), ... Full description.

This lesson, from the ISTAT (Integrating Science Teaching and Technology) Digiguide, uses information about recent earthquakes from the World Wide Web to involve 6-8th grade students in plotting earthquakes on a global map. Students may make weekly journal observations over the course of a year on the number of earthquakes and their distribution. The exercise may also be done over a few days. A before-and-after ... Full description.

These demonstrations are designed to help students develop a conceptual understanding of geophysical principles. The concepts covered in these demonstrations include rheology, seismic waves, reflection, standing waves, velocity, earthquakes, Earth density, magnetic field, resonance, precession, the shadow zone, and Curie temperature. Each demonstration provides background information and a complete ... Full description.

This page presents a description of the precession of the Earth, its relation to the precession of a spinning top, and Milankovitch's theory, linking precession (and orbital changes) with the occurrence of ice ages. Full description.

This easily built classroom apparatus is ideal for gaining a better understanding of how earthquakes work and how they are recorded. The apparatus consists of a heavy object that is dragged steadily with an elastic cord. Although pulled with a constant velocity, the heavy object repeatedly slides and then stops. A small vibration sensor, attached to a computer display, graphically monitors this motion, ... Full description.

In this activity, students create their own P- and S-wave travel chart and develop a better understanding of the relationship between the two wave types, travel times, and travel distances. Full description.

The properties of a rheid represent essentially all Earth materials: they behave elastically over short time scales and plastically over long time scales. In this demonstration, silly putty is used to help explain these properties as well as the yield strength of a material. Full description.

This demonstration elucidates the concept of propagation of compressional waves (primary or P waves) and shear waves (secondary or S waves), which constitute the seismic waves used in locating and modeling earthquakes and underground nuclear explosions, and for imaging the interior structure of the Earth. The demonstration uses a slinky, pushed along its axis to create a compressional (longitudinal) ... Full description.

This demonstration of how seismic waves reflect when they encounter a change in rigidity or incompressibility requires a helper to hold one end of a stretched-out slinky as stiffly as possible. The helper represents a material with a much greater rigidity than the slinky; waves can then be sent and reflected along the slinky. The site also discusses a demonstration of reflection from a less rigid ... Full description.

This site describes a demonstration of how the interference of seismic P (primary, compressional) and S (secondary, shear) waves cause standing waves such as surface waves in the Earth. The demonstration focuses on the P and S waves that are bouncing back and forth in the vertical direction in the Earth. Using a slinky, different frequencies are used to create different modes of standing waves. The ... Full description.