Read aloud: Everybody Needs a Rock by Bird Baylor. Students follow book's 10 rules to find a rock outside. Inside they scrub their rocks with old tooth brushes. Rocks get observed, weighed & tested for: luster/shine, hardness/scratched & streaked on a tile/true color. Rocks go home. Staple homework/rock tests to a paper lunch bag for students to bring a rock back in. They observe, weigh & streak again & do a comparative hardness test - take turns scratching their rock against a peer's- hardest ones rule!