In Diary of a Worm by best-selling author Doreen Cronin (hardcover copy included), the worm keeps track of the strange things he eats, such as his own homework. As students listen to the story, they can make their own slimy worms by combining the Worm Goo with the Worm Activator Powder. This kit makes about 40 feet of worms for a truly special introduction to polymer science experiments.
How Does It Work?
When you make String Slime, you’re actually learning about the science of polymers. The creative scientists at Steve Spangler Science coined the name “String Slime” but the real name of this liquid is sodium alginate. Sodium alginate is a long chain of molecules called a polymer. Polymers are large molecules made by linking many smaller, identical molecules together. Specifically, sodium alginate
is a polysaccharide taken from seaweed. Polysaccharides, such as starch and alginate, are made by linking together hundreds of glucose (sugar) molecules. Alginate is commonly used as a thickening agent for foods such as ice cream and fruit pies. Take a look at food labels the next time you’re at the grocery store to find out what other foods contain sodium alginate. Alginate compounds are also used for dental impression materials and wound dressings among other things.
The sodium alginate (String Slime Goo) instantly changes from a liquid to a solid the moment it touches the Activator solution. That happens because the Activator solution contains calcium, which serves to link the long polymer chains together. Scientists call this cross-linking.
For the scientists in the audience, here’s a more detailed description of what happens: a polymer strand is formed when the sodium alginate solution is added to a calcium chloride solution. This occurs because the Ca++ ions replace the Na+ ions and serve as a cross-linking
agent to link two alginate chains together. The resulting cross-linked polymer is insoluble in calcium chloride.
- 1 Hardcover Story Book
- 2 Bottles of blue Worm Goo (Size: 30 mL each)
- Worm Activator Powder (Size: 12gm)
- Full-color teaching and activity guide
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