Greenhouse Effect in the Classroom: A Project- and Laboratory-Based Curriculum

This article describes a multifaceted curriculum for use in earth science classes from secondary school to undergraduate level. The centerpiece of the curriculum is a project-based investigation of greenhouse warming that can be conducted during one or more lab sessions using off-the-shelf materials. This process provides students with the opportunity to gain a deeper understanding of the climate system, the nature of scientific uncertainty, the burden of proof in ongoing research, and the difficulties of transferring scientific results to the public-policy realm. The main thrust of the lab demonstration and the curriculum itself is to help students distinguish the solid science in these issues from the array of questionable information they encounter in the press, on the internet, or in conversation. Educational levels: Primary elementary, Middle school, High school, Undergraduate lower division

Earthquake Magnitude and Intensity

In this exercise, students compare the amount of shaking caused by historic earthquakes, and use data from seismograms to determine Richter magnitude. They will also investigate moment magnitude, an alternative to Richter magnitude, and calculate a seismic moment. In the second portion of the exercise, students investigate earthquake intensity and prepare a map of intensity values from the 1994 Northridge, California earthquake, using actual reports of its effects. Introductory materials explain the difference between earthquake magnitude and intensity, point out the logarithmic nature of the Richter scale, and present criteria for assigning modified Mercalli intensity values to a particular location. The exercise includes instructions, maps, data, and study questions. A bibliography is also provided. Educational levels: High school, Undergraduate lower division

Seismic Hazard Assessment: Conditional Probability

In this exercise, students investigate the use of conditional probability (the likelihood that a given event will occur within a specified time period) in assessing earthquake hazards. Introductory materials explain that conditional probability is based on the past history of earthquakes in a region and on how and when earthquakes recur; and discuss the different types of models that can be developed to predict recurrences. Using a table of probability values, students will calculate probabilities for earthquakes along the San Andreas and Wasatch Fault zones, and calculate probabilities that they will exceed a given acceleration (ground shaking) value. Example problems and a bibliography are provided. Educational levels: High school, Undergraduate lower division

Coastal Terraces, Sea Level, and Active Tectonics

In this exercise, students investigate the use of coastal landforms from ancient shorelines in studying tectonic movements. Introductory materials explain how coastal landforms are classified on the basis of sediment supply and positions of the land relative to sea level, and describe the features of erosional coastal terraces. Using data on the coastal terraces of San Clemente Island, off the coast of Southern California, students will construct a topographic profile, measure shoreline angles, and calculate rates of uplift of the island relative to the sea. The exercise includes a map and stereo pair, data on sea level fluctuations and ages of coastal terraces, and a problem set with study questions. A bibliography is also provided. Educational levels: High school, Undergraduate lower division

Balanced Cross Sections and Retrodeformation

In this exercise, students investigate the use of balanced cross sections and retrodeformation to study faults that do not break the surface and their application to tectonics, folding, and earthquake hazards. Introductory materials explain how to construct geologic cross-sections, the idea of balance in a cross-section, and the concept of retrodeformability, whether or not the structures seen in a cross section can be 'undeformed' into their original positions. Using the Kink Method, students will construct a cross-section and test a balanced cross section to see if it is retrodeformable. Instructions, a blank cross section with data, study questions, and a bibliography are provided. Educational levels: High school, Undergraduate lower division

Numerical Dating

In this exercise, students investigate methods used by geologists studying active tectonics for determining ages in actual numbers of years. Introductory materials describe the three most-used techniques for dating material formed during the Quaternary Period (approximately the last 1.65 million years), discuss the concepts of radioactive decay and half-life, and explain how these may be used to determine the numerical age of an object or substance. The exercise includes a set of problems in which students calculate isotopic abundance, half-life, decay rate, and absolute age. Example problems and a bibliography are provided. Educational levels: High school, Undergraduate lower division

Locating Earthquake Epicenters

In this exercise, students use data from the 1994 Northridge, California, earthquake to locate the earthquake and its time of occurrence, and plot data from Central and South America on a map to delineate plate boundaries. Introductory materials explain how earthquakes are caused, describe the types of seismic waves, and explain that the difference in arrival times may be used to calculate distance to the earthquake. Each portion of the exercise includes instructions, datsets, maps, travel-time graphs, study questions, and tables for entering data. A bibliography is also provided. Educational levels: High school, Undergraduate lower division

Orogenesis and Isostasy

In this exercise, students investigate the mechanism for the isostatic support of mountains. Introductory materials explain the Archimedes principle (the weight of a floating solid is supported by the weight of the fluid that it displaces) and the concept of depth of compensation (the depth within a fluid where the pressures generated by overlying material are everywhere equal), and graphically display the two hypotheses used to explain isostasy (Airy and Pratt hypotheses). They will then use these relationships to calculate heights and densities for icebergs floating in water, and use the Airy and Pratt hypotheses to calculate thickness and density of the crustal root of the Tibetan Plateau. Educational levels: High school, Undergraduate lower division