Each group needs:

• clear plastic tub (~12-in long × 6-in wide × 5-in deep) (~30-cm x 15-cm x 13-cm) with about 1 inch (2.54 cm) of sand in the bottom
• clay (~750 cm³), this clay does not need to be the high-quality type used for modeling; clayey or silty soil from your backyard works fine
• sand (~1500 cm³) (available at home and garden stores)
• gravel (~100 cm³) (available at home and garden stores)
• ~15 cotton balls
• (optional) tiny houses and buildings (such as Monopoly game houses and hotels), or any other simple representation to simulate the presence of a town sitting on the sand base
• Roles and Optimization Worksheet
• Budget Worksheet

Note: The amounts of clay, gravel and sand are approximate (based on experience with teaching the activity), but because students can choose how much of each type of material they want to use, it is helpful to have a bit extra on hand.

For the entire class to share:

• food coloring
• clear plastic tub in which to mix together food coloring, water and cotton balls ("garbage")
• (optional) gloves or spoon to "mix" the garbage
• strips of plastic garbage bags, to simulate geosynthetics used in landfills
• toothpicks
• straws
• popsicle sticks
• small, paper "Dixie" cups (~85 ml size), to measure and distribute clay, gravel and sand
• access to water
• watering can, water bottle or other "rain storm" device
• (optional) electric fan, to simulate the erosion force of wind
• (optional) graph paper