Cook up Some Watermelon Candy!

What can we use instead of a fine mesh strainer, blender, candy molds, or unflavored gelatin if we don't have them?

If you don't have a blender, use a food processor or mash chunks and use an immersion blender; strain the puree through cheesecloth or a clean thin dish towel instead of a fine-mesh strainer; use an ice cube tray or silicone muffin pan in place of candy molds; and if you can't find unflavored gelatin you can try agar-agar following its package instructions (it usually needs boiling and a different amount).

My candies didn't set or are still sticky — what likely went wrong and how do we fix it?

If candies don't set, confirm you measured 1 cup of strained watermelon juice, sprinkled two packets (about 4½ teaspoons) of unflavored gelatin over the cold juice and waited 1 minute before heating on low while stirring until fully dissolved, then chilled the molds flat for at least 2 hours, and if gelatin was expired or not fully dissolved, replace with fresh gelatin and repeat the heating and chilling steps.

How can we adapt the activity for different ages?

For toddlers let them wash the outside of the watermelon and hand chunks to an adult for cutting and blending; preschool/kindergarten kids can help pour blended juice through the strainer and measure the sugar; elementary-age kids (6–9) can sprinkle gelatin and help stir on low with adult supervision; and older kids (10+) can assist with heating and pouring into molds while an adult handles the hot saucepan.

How can we make the watermelon candies fancier or more personalized?

Stir in 1 teaspoon of lemon juice and a drop of food coloring into the strained juice before heating for brighter flavor and color, pour a thin layer into molds and chill until tacky before adding a second color for two-tone candies, or roll the popped candies in granulated or citric sugar after they set to mimic a sugared watermelon rind.