Ever wondered how heroes and heroines could leap through windows, shattering glass and never end up getting hurt? We are shattered to hear that movie action scenes are just clever stunts using clever materials. You can discover the cut throat truth by making your very own movie set with sugar glass.
Warning: This activity involves very hot sugar that burns and the sugar glass may have sharp edges that could cut. Have an adult present and take care when making and using.
What you need
a saucepan and stove top
1/2 cup water
2 cups white sugar
1/4 teaspoon cream of tarter
1/2 cup glucose, this can be found in supermarkets or health food stores
a baking tray lined with baking paper
a confectionary thermometer (optional)
What to do
Mix all ingredients in the saucepan and bring to the boil.
Leave it to boil for around 30 mins, until all the water has boiled off and the mixture is thick. You want it to be 150 degree Celsius when it is ready, so be very, very careful.
Pour mixture into the baking tray mould and let it cool. Have an adult present to do this part.
Allow it to cool, around 20 mins depending on how thick it is.
You can then use your stunt glass by creating a small movie set and seeing some smashing action of your own.
Tips
If you let mixture get too hot, it will start to go brown, and when it hits 175 degrees Celsius the sugar will burn and go black and gooey, so keep an eye on the stove.
Use it as soon as possible. The longer you leave your sugar glass in the tray, the stickier and gooier it will become. If you leave it in the sun or a moist area, it turns out just like toffee. It's still just sugar, so it may also attract ants.
Please be extra careful as the mixture retains its heat for a long time and can still burn your skin. Unfortunately, it doesn't taste too good either so bad luck there.
What's happening?
To make sugar glass, we dissolved sugar in water until we could dissolve no more. This is called the saturation point. This point changes with temperature, as the water becomes hotter, more sugar can dissolve.
When it cools, the sugar comes out of solution and wants to form crystalline shapes with each other. To create smooth, clear, sugar glass without crystals, there are a few things you can do.
You can add glucose syrup that gets in the way of the sugar molecules forming crystals.
You can also add an acid, which turns the sucrose into glucose and fructose. In this recipe, we used cream of tarter which is an acid made from wine grapes.
Solids have either crystalline or amorphous molecular structures. Both glass and crystal are amorphous solids, as they have molecules that are unorganized and all over the place. Examples of crystalline solids are common salt (NaCl) and diamond (carbon).
An amorphous solid can exist in a ‘glassy' or ‘rubbery' state. In our first attempt to make sugar glass, the sugar solution did not get hot enough and we made a lot of sweet and fun to play with stuff in a very rubbery state!
Sugar – the sweet and succulent stuff that we all crave is sucrose, a carbohydrate made from carbon, hydrogen and oxygen C12H22O11. This is just the simpler sugars fructose and glucose stuck together.
Applications
Sugar science is very useful in making sweets like fudge, toffee and lollipops!
Fact: Lollipops contain only 2 % water – the rest is sugar!
It is the temperature of the sugar that is important and lets you create all these different types of lollies.
