Water Filter Kit

How does a sand filter trap particulate matter?

This kit allows students to build filters containing sand, gravel, cotton and charcoal. Working in groups of two, students experiment with muddy water and salt water to discover the types of impurities that a sand filter can remove. In addition, when your students realize that a sand filter cannot trap dissolved salt, you can use the supplied background materials as an outline for a discussion of the problems associated with desalinization. Includes materials for 30 students: salt, aluminum pie pans, plastic cups, spoons, sand, gravel, cotton, clay soil, charcoal powder and complete instructions. Grades 5-8.