Kansas State Fair Demonstration Explanation & Recipes Presented by: NU Chemistry Club
Chemistry of Elmer’s Glue Active ingredients • Polyvinyl acetate • Polyvinyl alcohol
Chemistry of 20 Mule Team Borax • The main active ingredient is called sodium tetraborate decahydrate Tetraborate Complex Ion [B4O5 (OH)4]2-
Chemical Reaction • Cross-linking Polymerization • The borate ion forms hydrogen bonds with available hydroxyl groups of the polyvinyl alcohol and those that are created due to the reaction of the acetate groups of the polyvinyl acetate with water • Similar to forming the rungs of a ladder
Recipe for One Bouncy Ball • ½ - ¾ tsp. 40 Mule Team Borax • 2 T. Water & coloring (optional) • 1 T. Elmer’s Glue • To “color” your ball; add color to water, then stir in borax, then glue. Mix with a stirring stick until a ball forms; roll the ball between your palms until smooth and Bouncy!
“Classroom” Size Recipe • Pre-mix borax and water in a 4:1 ratio • i.e. 4 cups water, 1 cup borax (yields 32 balls) 6 cups water, 1 ½ cups borax (48 balls) • Shake or stir well; this will be a supersaturated solution. Allow sediment to settle. • Put 1 oz (33 cc) of liquid mixture in a small paper cup; add 1 generous Tablespoon Elmer’s glue to solution to make one ball. • 4 oz. bottle Elmer’s glue yields approx. 6 T. glue (1 T. per ball) and this size bottle is usually the cheapest!