Rock collection activity: an egg carton rock museum for K–2

1. Pass around two very different rocks. Ask: "Are all rocks the same?" Collect describing words on the board: smooth, rough, shiny, striped, speckled, heavy, light.
2. Students dip their rocks in water, dry them and look again with a hand lens. Point out that a wet rock often shows its colors and stripes better.
3. Sort round one: each student sorts the rocks into two groups by a secret rule (smooth or rough, light or dark). A partner guesses the rule.
4. Sort round two: students order the rocks from smallest to largest, or from lightest color to darkest, and place them in the carton cups in that order.
5. Students write or dictate a describing word for each row and give their museum a name.
6. Museum walk: half the class stands by their cartons while the other half visits and asks, "Which rock is your favorite and why?" Then switch.

Safety: collect only where it is allowed (taking rocks is not permitted in national parks), use rocks bigger than a grape for young students so none fit in a mouth, and wash hands after handling rocks and soil.

Differentiation: students who need support sort by one property only, with picture cards for smooth, rough, light and dark. Students who are ready add a fingernail scratch test and note which rocks leave powder. English learners can use the frame "My rock is ___ and ___."

Quick check: hold up one rock and ask a student for two describing words and the group it belongs in.

Save this activity to your library so it is ready when you need it.