I made ScienceFix.com to share my favorite demos that I do in my middle school science classes.  

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Video Demo: Watermelon Caviar

I recently started a food science club at school with a fellow teacher.  It's a good way for me to try out new stuff with a small group of students, that I eventually want to incorporate into my classes.  It's like a real life R and D department.  I recently posted about a polymer called sodium alginate. I got a response from Earl Lee on how to make watermelon caviar. So I decided, let's try it out with an after school club.  It demonstrates a technique used in molecular gastronomy. A polymer (which is in one of our standards), sodium alginate, is mixed in with watermelon juice. The mixture is then carefully inserted, with a syringe, into a solution of calcium chloride. A chemical reaction happens between the calcium chloride and sodium alginate to form calcium alginate. The calcium alginate is not soluble in water and thus forms a gel around the outside of the watermelon juice. The calcium alginate watermelon spheres are edible. We then experimented with making spheres of cola using the same technique.  The students loved the more intense (not to mention the more sweet flavor which their palettes are more geared to) flavor of the cola.


Video Demo: Flaming Gummy Worm

I usually do this demo with a Gummy bear, but all I had was Gummy worms, so that's what I used.  Sucrose has a lot of energy stored in the bonds that hold the carbon, hydrogen and oxygen atoms together.  With a little bit of activation energy (melting the potassium chlorate) and a large supply of oxygen gas, (supplied by the potassium chlorate) that energy gets released in the form of light and heat energy (exothermic).  

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