Kids, do you want to make some slimy, gooey worms for you and your friends? Of course you do! Here is what you will need. Have an adult partner buy some Gaviscon™ liquid antiacid and some calcium-fortified orange juice. Then all you need is some optional food coloring, a squeeze bottle with a narrow spout, a bowl (a shallow one works best), and a spoon. Fill the squeeze bottle with Gaviscon™ (here is where you can add food coloring if you like). Simply squeeze this into a bowl of the orange juice, and your worms should form instantly.
Please note: All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.
The longer the worms stay in the juice, the more rigid they become. You can lift them out using a pencil and touch them. Pull them apart to test how strong they are, for example, and if they get stronger the longer they sit in the juice (a few hours is best). What’s happening here? Your gooey worms are called polymers. A polymer is a large molecule made up of many smaller molecules linked together like a long chain. You can get an idea of this by hooking together a long series of paperclips. This chain represents the sodium alginate polymers in the Gaviscon solution. When these chains are put in the orange juice, the calcium ions (Ca2+) act to cross-link them. Make two paperclip alginate chains. Then, at a few points along the first paperclip chain, add dangling single clips and attach them to the other long chain. When you are done it should look a bit like a chain-link ladder. Imagine continuing this process to make a 3-D mesh, which happens the longer the worms sit in the juice.
The Gaviscon™ is needed because it has sodium alginate in the formulation. Sodium alginate is a commonly used thickener in ice cream, cheese spread, and even in the red pimento strips in green olives. Mixing this with the calcium ions that are in the orange juice forms the cross-linked polymer gel “worms”. You might also try calcium-fortified milk.
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Kathleen Carrado Gregar, PhD, Argonne National Labs
[email protected]
May 2004
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Reference: Check the “Stuff for Teachers” link at www.strangematterexhibit.com. This experiment is on page 25 of the Teacher’s Guide. Strange Matter is a traveling exhibition developed by the Ontario Science Centre and presented by the Materials Research Society with the support of the National Science Foundation.
