For the entire class to share

• 12 g calcium chloride (CaCl₂) Note: Alternatively, the teacher can use an already prepared solution (0.1M) and dilute as explained in the procedure section.
• 2 L distilled water (tap water can also be used)
• 10 g sodium alginate powder (food grade)
• 110 grams (4 oz) cost around $10; can order through Amazon or other suppliers.
• 3 different colors of food coloring/dyes (The bottles of food coloring can be shared among all the groups if needed)
• 1 L beaker to prepare the sodium alginate solution.
• 1 L beaker to prepare the 0.1M calcium chloride solution (stock solution)
• 2 250 mL beakers to dilute the stock solution and to prepare 0.05M and 0.02M calcium chloride solutions.

Each group needs

• 100 mL graduated cylinder (The teacher may choose a pipette or a syringe instead to add calcium chloride in several applications. The amount is specified in the procedure section.)
• 4 Styrofoam cups or 4 beakers (100 mL)
• 3 petri dishes (or 3 Styrofoam cups) for gelling