Each group needs:

• paper napkins, one per student
• dessert-sized plates or paper towels, one for each student, on which to place and eat the algal models

To share with the entire class:

• food grade sodium alginate (need 5 g for 1 liter of juice); such as 2 oz (56 g) for $12 at Amazon
• food grade calcium lactate (need 20 g for 2 liters of water); such as 1.8 oz (51 g) for $10 at Amazon
• low-acid fruit juice (pH > 3.6), such as pear, apple or carrot), ~100-250 ml juice per student; ~1 gallon is plenty for a 30-student class; for a no-sugar option, use distilled water that is safe for drinking (sodium or potassium added); alternatively, use tap water, although high calcium (hard water) can cause premature solidifying
• (optional) liquid food coloring, if using water instead of juice and want to color it
• water, ~4 liters
• 3 large bowls, each ~1-4 liters in size
• whisk or blender
• 1-2 three-inch fine mesh tea strainers or small sieves, such as the 3-inch fine stainless steel mesh strainer for $1.39 each at the Webstaurant Store
• 2 small ladles or spoons, each about 1-2 fl. oz in size
• laboratory scale, accurate to 1 g; alternatively, use a kitchen scale such as the Jennings CJ4000 4000g x 0.5g digital scale for $26 at Amazon
• paper or cloth towels, for clean-up

Cost note: The main expendable costs are for juice, paper towels and small amounts of the two reagents. The initial cost of the reagents is high, but only a very small portion is used.