Each group needs:

• duct tape (1 roll for every 4 groups)
• Budget Worksheet
• Cost Efficiency Worksheet, one per student

To share with the entire class:

• (optional, as a demo) the pumping mechanism from a hand soap dispenser (see Figure 2)
• hacksaw
• cordless drill with various sized bits
• ruler or tape measure
• stopwatch
• permanent marker
• a sink or other access to water
• 2 five-gallon buckets
• PVC pipe of various lengths and diameters; note: ¼", ½", 1 ½" and 2" schedule 80 PVC pipe form nice telescoping pairs; lengths such as 1", 6", and 1 ft are nice to work with; plan for three of each size per group
• various PVC pipe joints: elbows, Ts, and joiners matching the PVC sizes selected are useful; 3-4 per group
• various sized rubber washers. Sizes that match the PVC diameters are useful (1/4", ½", 1 ½" and 2")
• threaded rods and nuts: 1/4-20 threaded rod is a nice standard size; consider pre-cutting into 1-2 ft lengths for students; plan for up to one rod per group, with up to 6 ¼-20 nuts per group
• assorted small springs: allow for 2-3 springs per group
• scrap wood: assorted sizes and lengths
• assorted wood screws

Materials notes: These materials are available in the plumbing and hardware sections of hardware stores. Feel free to incorporate other materials as well, to encourage creative design. Many communities have re-used building supply stores, and old machinery parts or other odd parts make great additions.