Each group needs:

• disposable diaper
• large bowl or plastic tub
• gram scale
• petri dish or small plastic condiment cup
• sharpie
• spoon for stirring
• beaker or some other container to mix the hydrogel
• weighing boat or small plastic condiment cup
• 50 mL boiling water
• paper towels
• safety goggles (one pair per student)
• Hydrogel Lab Sheet

For the entire class to share:

• whiteboards
• whiteboard markers
• box fan, drying oven, or clamp light
• chemicals to create hydrogels (amounts are enough for 6 groups using the given combinations below):
• 8 g agar
• 8 g hydroxyethyl cellulose [HEC] reagent grade powder
• 8 g sodium carboxymethyl cellulose [CMC] powder
• 6 g citric acid

Student groups can research and create their own compound for the hydrogel, or they may use the amounts and combinations given below. The following are the amounts needed for six lab groups. If there are more than 6 lab groups, some groups can test the same combinations to compare results. This amount fits into a standard plastic petri dish.

• Combination 1
• 4 g agar
• 1 g citric acid
• 50 mL hot water
• Combination 2
• 4 g HEC
• 1 g citric acid
• 50 mL hot water
• Combination 3
• 4 g CMC
• 1 g citric acid
• 50 mL hot water
• Combination 4
• 2 g HEC
• 2 g agar
• 1 g citric acid
• 50 mL hot water
• Combination 5
• 2 g HEC
• 2 g CMC
• 1 g citric acid
• 50 mL hot water
• Combination 6
• 2 g CMC
• 2 g agar
• 1 g citric acid
• 50 mL hot water