Making edible crystals

Last week, kids had requested for some interesting Chemistry experiments. I decided to surprise them with some yummy treats and I readied some sugar and salt crystals for them to see. It was pretty easy for them to guess that the experiment was with crystals.



What is a crystal?

Crystals are solids that form by a regular repeated pattern of molecules connecting together. In crystals, a collection of atoms, called the Unit Cell, is repeated in exactly the same arrangement over and over throughout the entire material.


Materials needed

We discussed about different crystals , their structure and where you will find them.
Then it was time to do hands on work. We prepared a saturated solution of sugar by dissolving:

1. 1 cup of water
2. 3 cups of sugar


Sugar dissolved in hot water

Procedure 

Boil 1 cup of water and dissolve  3 cups sugar in it. Beyond a certain point the sugar will not dissolve and forms a 'saturated solution'.  After cooling a bit, pour it into 2 bottles, to which you can add different food colors. Here we added red and green food colors. Leave a popsicle stick in it by coating it with sugar, guiding the crystal formation.  Put a small tissue paper and cover the bottle. Now wait for a few days for the crystals to form.
Explanation

Once the saturated solution starts to cool down, it becomes supersaturated. A supersaturated solution is unstable—it contains more solute (in this case, sugar) than can stay in solution—so as the temperature decreases, the sugar comes out of the solution, forming crystals. The lower the temperature, the more molecules join the sugar crystals, and our rock candy is ready!

 

Tasty treats for the kids! Yum!


  

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