How To Teach Science… With Candy (Part 2)
Last week you learned that nearly all of the candy we know and love comes from a heated solution of sugar and water. But even with these few ingredients, cooks have learned how to manipulate several of the variables in the cooking of this solution.
However, the temperature of the syrup not only affects the TYPE of candy you can create –
It affects the TEXTURE of the candy too!
The way in which cooks can alter the texture of candy has EVERYTHING to do with the four basic concepts of science:
These four concepts are very important as your candy cools and forms its own unique texture. These concepts play a big role in the creation of your candy, especially if you want the smooth texture of fudge or the rough and jagged texture of rock candy.
GAZE INTO THE CRYSTAL BALL…
Fudge and rock candy have COMPLETELY different textures! The reason for this change has to do with the number and size of the crystals in the syrup. If you recall from our discussion on ice cream, a crystal is a mass of ATOMS or molecules bonded together in an orderly fashion, like soldiers in formation. The cool thing about crystals in your syrup is that they will continue to bind with other similar ATOMS or molecules that are moving around in the fluid.
Think of a line of children, all holding hands, running around a playground. The two children at the ends of the line can grab other children as they move around the playground and increase their size. This is how a crystal grows as well!
And there is one simple rule to follow about crystals whenever you are making candy:
HOT SYRUPS FORM ROUGH, JAGGED CRYSTALS AND COOLER SYRUPS FORM SMOOTH, SMALLER CRYSTALS
But how does this work? It’s simple…
As you probably have guessed, the ATOMS within your heated solution of sugar water absorb energy from you stove as its temperature increases. This energy DIFFUSES into each of the ATOMS, causing them to bounce around and into each other quite a lot.
Because of all this bouncing going on, it is harder for molecules to line up, bond with each other in an orderly fashion, and form a crystal. So, hot syrups do not make many crystals because of all the energized ATOMS bouncing into each other!
To go back to our previous story… it would be very difficult (not impossible) for a line of children to form on the playground if they were running around as fast as they could. Think about it… as a line of kids would form, they could easily get broken apart by individual children slamming into them! The few lines that would form could get VERY large as they have so many extra children to grab onto. This is the same with crystals in a hot sugar solution.
Once crystals can form inside a hot sugar solution, other sugar molecules will tend to bounce into this crystal and bind with it – making a larger crystal! Therefore hot syrup will have a lower DENSITY of sugar crystals but each crystal will be MUCH larger than crystals in cooler syrup.
THESE LARGER CRYSTALS GIVE HOT SYRUP A VERY ROUGH AND JAGGED TEXTURE WHEN IT COOLS
Okay. Are any ATOMS created or destroyed during the formation of crystals? Nope! It may seem like something strange is going on when you witness the growth of a crystal, but you know for certain that all of this movement follows the LAW OF CONSERVATION! There’s no way any ATOMS are being created during crystal formation, only rearranged into new (and sometimes tasty) forms.
Learn more about chemistry concepts (and many more) in the Classic Science: Series for the Family and be certain to come back every Thursday or subscribe to The Blog of Mr.Q to learn more about how to teach science during breakfast, lunch, and dinner!
