For a class of 20 (10 groups of 2):

• 10 soap dishes (no lid necessary)
• 10 plastic bowls (cereal bowl size)
• 30 rubber bands (10 each of 3 different thicknesses)
• 5 shoe boxes of any size (with or without lids)
• 5 toothbrushes
• 10 pencils
• 5 pint-sized drinking glasses
• three 8.5' x 11-inch notepads
• tape
• scissors
• springs (available at hardware stores, educational supply stores or online; best are springs ~2-3 inches long)
• (optional) other supplies suitable for construction of musical instruments