Go outside and find an outcrop-a roadcut, cliff face, or other site where rocks are exposed. These are ideal places for practicing field geology. Professor Cotter gives tips on safety, maps, tools, and techniques. A notebook and careful record-keeping are essential. Amateur geologists can make important discoveries, so field geology is your chance to advance knowledge while enjoying the outdoors.

Stressing that he is not a medical doctor, Professor Cotter delves into the healthful and harmful effects of geologically sourced substances. Some have proven benefits, such as the antibacterial properties of salt and copper. Others can be deadly. For example, radon, a gaseous product of radioactive decay, causes lung cancer. Asbestos, a fibrous silicate mineral, is similarly dangerous to breathe.

Metamorphic rocks form under conditions halfway between those of sedimentary and igneous rocks. A good analogy is the process of glacier formation that turns snow into dense, interlocking crystals of ice. Focus on foliated metamorphic rocks, such as slate and gneiss, which have lineation patterns. Geologists can read these patterns to reconstruct ancient mountain ranges and plate boundaries.

Sedimentary rocks make up a substantial majority of rocks at Earth's surface. In this episode, focus on clastic rocks, which are composed of broken fragments of pre-existing rocks. The fragments can vary in size from clay particles to silt, sand, gravel, and larger pieces. Learn how these rocks form and the rich stories they tell about the past.

Having learned about sediments, sedimentary environments, and how fossils are preserved, you are ready to go fossil hunting! Professor Cotter prepares you with background on rules and regulations, strategies for finding the best sites, and how to photograph and collect specimens. He closes with a quiz, challenging you to predict the types of fossils associated with different geologic formations.

Consider how to put your knowledge of geology to use. Issues faced by your community may benefit from geologic insights about groundwater, watersheds, roadways, pollution, and historic questions such as abandoned mines and quarries. Practical geology will only grow in importance as the world deals with climate change, resource shortages, and the pressing need to live in harmony with the planet.

The most highly prized rocks among non-geologists are gemstones. This episode covers all 12 birthstones, plus other gems, probing the shifting categories of precious and semi-precious gems. You learn how gems form and where to find them. Even more difficult to find are meteorites. Hear tips for identifying these extraterrestrial rocks, which are unlike anything native to Earth.

Steppes and deserts make up almost a third of Earth's land surface and are an ideal place to practice geology due to the distinctive landforms, often unobstructed by vegetation. Explore alluvial fans, washes, playa lakes, dunes, and other features typical of arid regions. Also ask why steppes and deserts are so dry. What combination of surface, ocean, and atmospheric conditions produce them?

Visit the beach with a geologist's eyes and see how the interaction of waves, ocean currents, and winds lead to the ebb and flow of sediments and blending of landforms. Consider the four types of waves and what they reveal about the ocean floor just offshore. Also, zero in on individual grains of sand, identifying their minerals and tracing their origin. Reflect on why beaches are sandy at all.

Investigate glaciers, which now cover about 10% of Earth's land area; 25,000 years ago, they covered 30%. Learn how to spot evidence of past glaciation-from sculpted valleys in Yosemite National Park, to the cliffs at Vicksburg, Mississippi (which formed far from glaciers), to Minnesota's 10,000 lakes. Dig into the physics of glaciers: how they develop and the forces they exert.