After the summer nesting period, broad winged hawks are known for migrating nearly 10,000 kilometers, (6,200 miles) each fall from their breeding grounds in North America to tropical biomes in South America, where they spend the winter. The International Union for Conservation of Nature has labeled broad-winged hawks as a species of "least…

Continental margins are an important part of the ocean floor. They separate the land above sea level from the deep ocean basins below and occupy about 11% of Earth's surface. They are also economically important, as they harbor both mineral resources and some of the most valuable fisheries in the world. In this article students investigate North…

Knapping is a toolmaking technique used by early humans and replicated by research archaeologists. Describes knapping techniques and provides examples of how they are presently being used in North America. (MDH)