How have the materials we use in day to day life changed over time? Objective Students will: Identify three arts and crafts from Mandan, Hidatsa and Arikara tribes. Discuss the importance of flint in the geography and economy of the Hidatsa during the Knife River village days, what flint was used for and identify what has replaced flint today. Describe other locations throughout the United States where Knife River flint has been found. Background This lesson is part of Knife River Indian Villages National Historic Site Teacher's Guide for Grades K-8: Guide to the Earthlodge People . It was wri Duration: 60 Minutes.