By Randi Lynn Mrvos
In the early days of Hollywood, candy glass was used in cowboy saloon fight scenes. Bottles made of sugar were cracked on actors' heads, shattering into harmless jagged shards. Candy glass not only looks like real glass, it also shares some of the characteristics with the real glass, except it is safer.
Candy glass functions like real glass in movie stunts because it is an amorphous solid. Amorphous solids, like rubber, plastic, and glass are made up of randomly arranged molecules. The lack of molecular order of candy causes it to easily break into realistic-looking pieces of glass. If candy molecules were assembled in an orderly, crystalline structure, the candy would be tougher to break. Though candy glass is similar to glass in its molecular arrangement, its chemical composition makes it safer to use than real glass.
Both candy glass and real glass are made by combining a base material (glass-former) with an additive. Glass is primarily made from silica--a mineral found in most rocks and in sand on beaches. Although silica is one of the best glass-formers, it takes a very high temperature of 2876° F (1580° C) to melt. To lower the melting temperature of silica, lime (CaO) and soda ash (Na2CO3) are added. Similarly when making candy glass, sugar (or sucrose) is a good glass former and water serves as the additive. Unlike real glass that is usually made when 75% sand (silica), 15% soda ash, and 10% lime, are melted at 1292° F (700°C), sucrose has a melting temperature of 367° F (186° C), and water has a melting temperature at 32° F (0° C). The lower melting temperature makes candy glass easier to produce.
Candy glass not only looks like real glass, it is made in a similar manner. Just like a glass blower, a specialist (sugar blower) trained in the art of sugar blowing can create a variety of shapes. To make a breakable bottle for a stunt, the specialist prepares a basic recipe of hard candy, which remains solid at room temperature. By using heat lamps, the sugar blower softens the solid candy until it forms a ball. The sugar ball is then attached to a blow pipe. Carefully, the sugar blower blows through the pipe, enlarging the air chamber inside the candy and shaping the outer surface with his/her fingers to form a bottle.
Today, new materials, such as special thin plastics and paraffin have replaced candy glass in movie sets. To make a breakaway glass window for a movie stunt, cellophane is tightly stretched over a wooden frame. A smaller, metal frame that has the same dimensions as the window needed
for the movie prop is placed inside the wooden frame. Both frames are placed on a hot aluminum table. The cellophane shrinks and forms a smooth tight surface on the metal frame. Pellets of plastic resin are melted with heat and poured into the metal frame. The frame with the 'hot glass' is placed on a level table to cool. When the metal frame is removed, an authentic-looking sheet of glass is ready for a sensational stunt. In the latest James Bond's movie, Die Another Day, polyurethanes and silicones were used to create a spectacular ice palace. In a daring high speed car stunt the huge ice palace doors were shattered, making it the biggest single use of breakaway glass in the movies.
Although candy glass has been replaced, it has been used occasionally for movie stunts, as in The Poseidan Adventure (1972), The Birds II (1994), and Police Story I (1985). In a dramatic fight scene at shopping mall in Police Story I, Jackie Chan smashes through special double-thick glass shop windows, leaving sharp fragments embedded in his skin. Daunting, isn't it? But now you know the secret--it was only a sweet stunt!
Clise, Rick, Special Effects: A Look Behind the Scenes at Tricks of the Movie Trade", Australia, Vicking Kestrel, 1986, pp. 10-11.
Fry, R., and Fourzon, P., The Saga of Special Effects", NJ, Prentice-Hall, Inc., 1977, p.174.
Animatronic Whale, Bond Film a Smash Hit for Bentley Chemical
Behind the Scenes
Calculators and Conversion Tables
Crystalline and Amorphous Solids
Holiday Candy
How is Lollipop Like Glass
Learning the Principles of Glass Science and Technology from Candy Making
Police Story (1985)
Research Help, ICEM Safecards on Workplace Hazards Silica Dust
Types and Uses of Sugar
With the help of an adult, you can make candy glass. You will need a large pot and a candy thermometer.
Mix together 7 parts white sugar, 3 parts corn syrup, and 2 parts water.
Let ingredients come to a boil without stirring, until the mixture reaches 300° F (150° C). This will take about 40 minutes.
When the mixture reaches 300° F, immediately pour it onto a large flat surface, like a cookie sheet. Remember the mixture is very hot, and when it cools it's fragile and sharp.
Randi Mrvos is a homeschool teacher and a freelance contributor for Weeones, an educational e-magazine for children. Her publishing credits include The Christian Science Monitor, Highlights for Children Magazine, Scholastic Books, The Lesson Plans Page, and Parents and Children Together Online Magazine. She lives in Lexington, KY with her husband, Jim and eight-year old daughter, Abby.
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