Twinning, Polymorphism, Polytypism, Pseudomorphism
This site is a lecture by Dr. Stephen Nelson from Tulane University that discusses the various nonstandard forms of crystal growth that are characteristic to some minerals. Topics include twinning (contact and penetration, polysynthetic and cyclical), the origins of twinning, and twin laws in the triclinic, monoclinic, orthorhombic, tetragonal, hexagonal, and isometric systems. Various types of polymorphism in many minerals are discussed as well as polytypism, metamict minerals, mineraloids, and
Nonlinear physics is a catch-all term for the study of the dynamics of driven, open, non-equilibrium systems. Our group is mainly concerned with the phenomenon of pattern formation. When a nonlinear, dissipative system ( that is, one with friction ) is driven hard enough, it will often undergo a symmetry-breaking instability which takes it to a regular pattern state. The pattern is a dynamical state sustained by the driving forces which can have a high degree of periodic order and symmetry, even
The Atmosphere And Its Relation To The Crust And Hydrosphere
This site provides an illustrated lecture from a geochemistry course offered by Dr. Scott Wood at the University of Idaho. Topics include a review of the structure and formation of the Earth's crust, atmosphere, and hydrological cycle, and the composition of the atmosphere. Additional topics covered are the concept of residence time, geological and biological sources of components in the atmosphere, acid-base theory, Henry's law and the solubility of gases in water, primary and secondary air pol
Stereographic Projection of Crystal Faces
This site features a lecture by Dr. Stephen Nelson from Tulane University that explores a systematic way to define crystallographic angles. The lecture discusses crystallographic angles and gives an introduction to the use of stereographic projections for depicting the angular relationships between crystal faces. Scientific illustrations clarify the text.
Origin Of The Universe And The Abundance Of Elements
This resource features an illustrated lecture from a geochemistry course offered by Dr. Scott Wood at the University of Idaho. Topics include the Big Bang theory, the evolution of stars, the relative abundances of elements in the Universe, and some fundamental nucleosynthetic processes that explain elemental abundance patterns. The lecture presentation may be downloaded as a PDF document or a PowerPoint presentation. Reading assignments and a homework problem set with answers is also provided.
This site features a collection of visual resources about glaciers. Diagrams, images and animations reveal how a glacier forms, advances and retreats. These resources can be integrated into lectures, labs or other activities.
Radioactive Decay and Absolute Age Determinations
This site provides access to a number of visual resources and supporting material illustrating the concept of radioactive decay and its central role in radiometric dating. Visualizations include diagrams, graphs, static illustrations and photos. Resources found on this site are suitable for use in lectures and classes and may also be used as the basis for labs or other activities.
This site provides visual resources and supporting material about the study of sequence stratigraphy. Resources accessible from this site include informational text, images, animations and short videos which can be integrated into lectures, labs or other activities.
This site features a collection of visual resources that can be used to help illustrate the process of physical weathering. Visualizations demonstrate different styles of mechanical weathering and the resulting impact on the landscape. Resources include animations, interactive graphics and photographs showing the effects of physical weathering. These visualizations are suitable for use in an introductory level geology lecture, lab, or other activity.
Metamorphic Phase Diagrams
This site is part of a petrology course offered by Dr. Steve Dutch at the University of Wisconsin at Green Bay. Topics covered include the phase rule, metamorphic phases and phase diagrams (including ACF diagrams, A'KF diagrams, AFM diagrams, and CaO-MgO-SiO2 diagrams), and their evolution. Colorful diagrams accompany the text.
Tectosilicates, Carbonates, Oxides, & Accessory Minerals
This site from Tulane University consists of a lecture by Dr. Stephen Nelson on tectosilicate, oxide and carbonate minerals. The site features a table and description of the minerals in each group, including the nine types of SiO2, the different feldspars, and the calcite group. Optical and physical properties are explained, as well as the environment in which each mineral crystallizes.
Observe River Erosion Creating Waterfalls and Chasms
This animation illustrates the processes involved in waterfall formation. Related features such as chasms and plunge pools, as well as headward erosion and migration are also portrayed. Users can stop, play, fast forward and rewind the animation at any time. This visualization is one of several animations in a series developed as a component of Exploring Earth, a website that supports the textbook Earth Science.
Animation of Wave Motion
This Flash animation illustrates wave motion, or the movement of energy through water. Users can stop, play, fast forward and rewind the animation at any time. This visualization is one of several animations in a series developed as a component of Exploring Earth, a website that supports the textbook Earth Science.
Mountains and Mass Wasting
This lecture discusses physical and chemical processes that break down rocks and rock debris transportation mechanisms. Physical weathering includes abrasion, fragmentation, frost wedging, and thermal expansion and contraction. Chemical weathering includes solution, oxidation and hydration, and hydrolysis. The lecture notes are supported by images such as photographs, satellite photos, and diagrams depicting glacial features and frost wedging.
Part of the supporting resources for the School of Earth Sciences dynamic earth module, the -Why Topography?- site discusses two models introduced in the 19th century that are still used to explain topographic variations. These models are the Pratt and Airy models of isostasy. In the Pratt model, high topography (relative to surroundings) is due to lower density whereas in the Airy model, high topography is due to thick crust.
Impact of the Seasons on Earth Systems
This site features Flash animations that illustrate how seasons impact various Earth systems, including surface temperature, latent heat flux, air temperature, net radiation, precipitation, runoff, and soil moisture. These resources are suitable for use in lectures, labs, or other teaching activities.
Atmospheric Pressure and Wind Animations
This site features Flash and QuickTime animations that illustrate diurnal changes in wind patterns along coasts due to unequal heating of the land and water, the Coriolis Effect on the Earth's surface and in the context of everyday weather patterns, and global circulation, temperature, and wind patterns. The animations can be paused and rewound to stress important points. These resources are suitable for use in lectures, labs, or other teaching activities.
Cause of Seasons Animations
This site features Flash, QuickTime, and GIF animations that illustrate the cause of seasons, how seasons impact the sun's apparent path across the Earth's sky, the subsolar point, and the circle of illumination. The animations can be paused and rewound to stress important points. These resources are suitable for use in lectures, labs, or other teaching activities.
Petrography and Petrology
This site is the home page for the petrography and petrology class at Brock University. The site presents general information about igneous petrology, nomenclature and classification information, modal and normative analysis, and the chemistry of igneous rocks. Further topics discussed include fractionation, hybridization and assimilation, and fractional crystallization, as well as types of metamorphism, compositional groups, and Barrovian metamorphism. The information is presented as a sequence
Martin Van Buren's "Return to the Soil"
is a curriculum-oriented site using the home, named Lindenwald, the eighth President moved to after his term in office to introduce a discussion of Van Buren and his times. The site contains photos and drawings of Lindenwald as well as discussions how Van Buren interacted with other political leaders of the day, like Andrew Jackson and John C. Calhoun. The site offers many questions and suggestions for student assignments.