Finally, here is my hot post that disappeared into the ether last night. Thanks so much to Julie K in Taiwan, Angi and Nature Mama for having the brilliant idea of emailing me the post from their Google Readers. That saved me at least an hour of rewriting! I was so down on computers this morning, but this evening I am uplifted by the fact that three people I have never met in “real life” can help me out! Thank you!!! Now, on to the post:
The theme for this week’s Unplugged Project was hot. Finally, we managed to get back on schedule and do it, although we broke away from our usual craft project and went in a more scientific direction.
While away this summer, I found a number of good books in my Dad’s favorite thrift store (he’s a packrat too). One is called Science Experiments You Can Eat by Vicki Cobb (more about the book at the end of this post). While we were trying to come up with hot ideas, my 7 year-old daughter picked up this book and wanted to choose a food-related project. We decided on Caramel Syrup: Sugar Decomposes from the Kitchen Chemistry chapter.
Older children will find this scientifically interesting and fun to do. Younger kids will enjoy the end result!
The goal of the experiment is to teach about chemical compounds and how they can sometimes be broken down into completely different substances. Although I always liked science in school, I am not a chemist so forgive me if I am not 100% perfect in my description.
Since I am a terminal nerd, I didn’t trust the book’s very simple explanation, and actually researched sugar and how it decomposes. I learned that sugar and its breakdown process is rather complicated. (If the mysteries of caramelization keep you awake at night, then read this.)
I tried to keep it 7 year-old simple and explained to my daughter that sugar is actually carbon and water fused together. When you heat sugar, it breaks down into its original carbon and water elements. I showed her the scientific formula for table sugar (sucrose): C12H22O11 . She already new that H2O was water and could see that in the formula. After I explained that C meant carbon, she saw the carbon and water in the formula.
Heating the sugar would cause it to become watery (the release of the water) and dark (the carbon). It would no longer really be sugar.
What we needed – sugar, water, a heavy frying pan:
First my daughter poured half a cup of sugar into the frying pan:
We heated the sugar over medium-high heat and my daughter stirred it:
After about 5 to 10 minutes, the sugar started to melt:
As my daughter continued stirring, the sugar melted further and began to darken and become very watery:
Finally it turned “straw-colored” and we had transformed our sugar into a new substance – caramel. We turned off the heat and slowly added half a cup of water in order to create a runny, edible solution. I did the pouring as the caramel was so hot that it steamed and spattered:
The shock-cooled caramel formed a brittle sort of candy-lump that we just had to taste:
My daughter continued stirring the mixture on low heat for about another ten minutes – until the big caramel chunk dissolved into a solution:
This is what we ended up with: a delicious carbon-water mixture that we ate over ice cream!
If you haven’t heard of Science Experiments You Can Eat and you have scientifically-inclined children (or you homeschool), you might want to check it out of the library. Ours is an old version (1972), but the new one is supposedly revised and updated. I haven’t seen the new one, but our book has the following chapters about the science of food: A Kitchen Laboratory; Solutions; Suspensions, Colloids, and Emulsions; Carbohydrates and Fats; Proteins; Kitchen Chemistry; Plants We Eat; Microbes; and Enzymes.
Next week’s Unplugged Project theme will be: