Each group needs:

• all-purpose 23 cm x 33 cm (9” x 13”) aluminum baking pan (the same one may be reused for improved iterations of the design)
• 0.5 L (2 cups) natural decorative sand; the amount may be varied as long as each group gets the same amount; if available, students may also be provided with different types of sand to test which type would be the most absorbent) 
• 0.75 L (3 cups) artificial grass and/or moss
• 0.5 L (2 cups) rocks and/or pebbles
• diaper (per group and per iteration)
• 10 toy logs
• 2000 mL of water

Each student needs:

• lab notebook
• pen or pencil

For the class to share:

• 3 spray bottles
• 1 large beaker
• measuring cups or plastic cups of the same size