Tuesday, January 8, 2013

SMMART SCIENCE: Guest Post: Loralee CandyExperiments.com

The Incredible Growing Gummi Worm

GUEST POST From Loralee at www.CandyExperiments.com

Gelatin is amazing stuff.  A small amount of gelatin absorbs a lot of water, creating a huge, solid mass.  For example, the 18 grams of gelatin in one box of JELL-O mix can absorb four cups of water.

The tiny amount of gelatin in a Jell-O packet can absorb four cups of water to create a solid.

Gelatin contains long protein molecules that tangle together.  As these molecules form bonds, cross-linking like a jungle gym, they trap water molecules between them.  Because gelatin absorbs so much water, candy containing gelatin acts like a sponge. A single tiny candy submerged in water can swell to an enormous size.  That’s what makes “The Incredible Growing Gummi Worm” one of our favorite candy experiments.

To turn a gummi worm into a “gummi snake,” fill a flat dish with water and drop in a gummi worm (or several).  Set aside a dry gummi worm for later comparison.  Check back every few hours to see your gummi worm growing, since it can continue to absorb water for up to two days. 

Once your gummi worm has grown to its full length, you can perform tests to see how much it grew. 
  • Use a ruler to measure the length of the giant gummi worm, then measure the dry gummi worm and compare. 
  • Weigh it and compare its weight with a dry gummi worm.  Be gentle, because a water-engorged gummi worm becomes fragile and splits easily, like Jell-O.  Try moving it by tipping most of the water out of the dish, laying down some plastic wrap, and sliding the gummi worm onto the plastic to weigh it. Then weigh a dry gummi worm and subtract it from the weight of the giant gummi worm.  The remainder is the weight of all the water that was absorbed.

You can also try this activity with other gummi candies, like fruit snacks or Life Savers Gummies.  Check the ingredient labels to make sure that your experimental gummies do contain gelatin.  Gummi candies without gelatin, like Swedish Fish, don’t absorb extra water. 

“The Incredible Growing Gummi Worm” is just one of dozens of candy experiments in Loralee Leavitt’s new book, Candy Experiments.  Order from Amazon.com, Barnes & Noble, or visit her book signing in Salt Lake City at the King’s English, Sat Feb 16 at 2:00 pm.  You can also follow her candy adventures online at www.candyexperiments.com.

For more information:

2010 Harvard Food Science Lecture #8: Gelation

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