Listen to Dr. Lisa Chirlian show Kathy the science behind making pudding!
- follow along with the steps below!
Take care! The syrup formed in the recipe gets extremely hot. Please make this recipe as a family—with plenty of adult supervision.
In the movies, glass often breaks. People fall through windows, or one character breaks a bottle and glass flies everywhere. Today, to keep actors safe, synthetic materials are often used instead of glass. But, in the past, people used sugar to make material that appeared to be glass, but could be easily and safely broken.
Sugar can also be used to make beautiful art that looks very much like colored glass. Usually, sugar is not transparent—sugar crystals appear white. But, when heated to a high temperature, sugar crystals can be transformed into a glass-like state. Why can sugar crystals be changed into a glass? Both sugar crystals and sugar glasses are solids, but the arrangement of the sugar molecules is different. We can’t see the individual molecules—what we do see is many, many molecules organized in a particular way. When you buy sugar, it is in crystalline form. Each little grain or crystal of sugar is made up of lots of individual sugar molecules. The molecules are arranged in a very orderly fashion that gives sugar crystals their shape. The molecules stack together like bricks, and give the crystal distinct edges. When you eat sugar, your tongue can feel these edges. When sugar is heated, the crystals melt and loose their regular shape. Heat the mixture hot enough and the sugar may solidify in a glass-like state, rather than in crystals.
To help make sure that a glass is formed instead of crystals, corn syrup and cream of tartar are added to the mixture. Both corn syrup and cream of tartar prevent the sucrose molecules from reassembling into crystals and instead form the glass. Adding food coloring to the hot mixture allows the color to be incorporated into the finished product.
Caution: The sugar/water solution is extremely hot. Please take care when mixing and pouring it.
1 and 3/4 cups sugar
1 cup water
½ cup corn syrup
1/8 teaspoon cream of tartar
Aluminum foil (disposable) pan (two 8 inch cake pans work well)
Procedure: 1) Put the sugar in the pan. Add the water and stir gently to mix. 2) Add the other ingredients and stir gently. 3) Heat the mixture slowly, stirring constantly until the solids dissolve and the solution comes to a low boil. 4) Stop stirring and attach a candy thermometer to the pan. Heat until the temperature on the thermometer measures 300 oF. 5) While the mixture is heating, spray cooking spray on the aluminum pans. (Do not leave the mixture unattended!) 6) When the temperature reaches 300 oF, carefully pour the mixture into the aluminum pans. The pans will get very hot, so be sure they are on a hot plate, or other safe surface. 7) Add drops of food coloring and use toothpicks to swirl a design. Let cool and remove from the pan. Be careful! The sugar glass is delicate, but will last if treated gently and kept away from moisture. Sealing the sugar in an airtight container will also help keep bugs away.