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Get ready to watch some cool crystals grow and when you're done, you can eat them!
Optional: To make your rock candy more colorful, try adding 1-2 drops of food coloring to your sugar solution before putting the string in.
In step two you made a saturated solution -- there was so much sugar in the water that the water didn't have room to dissolve any more, so some was left in the bottom of the pan. When you dipped the string into the solution in step five, some of the dissolved sugar stuck to the string. Once the saturated solution started to cool, the loose sugar molecules in it (called the solute) started to join with the sugar molecules on the string. Then, the water molecules (called the solvent) started to evaporate or dry up into the air, leaving sugar molecules behind. Those molecules gradually joined with the sugar molecules on the string and became crystals. Because all of the solute molecules are the same (they are all sugar), they all form the same shape of crystals and they all stick together, making a big chunk of sugar crystals that are pretty to look at and tasty to eat!
Note that this is a special science project that is safe to eat because you only used food products, not any chemicals, and you used clean dishes from your kitchen. Never eat any experiment unless it is made entirely out of food and you only used clean dishes to prepare it.
In this project you can grow crystal snowflakes from a chemical called Borax and use them as pretty winter decorations!
Optional: To make colored snowflakes, use colored pipe cleaners and add 1-2 drops of food coloring in step four. To make your snowflakes glow in the dark, paint the pipe cleaner snowflake with glow-in-the-dark paint in step two and let it dry completely before going on to step three. Tie a ribbon to one point of your snowflake to make a Christmas tree ornament!
Just like in the rock candy project, you made a saturated solution of Borax, which is a chemical that forms crystals when the conditions are right. By mixing it with hot water and letting it cool and having something for the Borax (solute) molecules to attach to (the pipe cleaner snowflake), you gave the solution the right conditions to grow crystals! Once the crystals started to grow on your snowflake shape, more and more crystals formed around them. Ice crystals that real snowflakes are made of are not quite like these Borax crystals, but they do look sort of similar and they both are pretty and sparkle when light shines on them. Real ice crystals are made only of water. The difference is that they are formed when water vapor in clouds freezes and falls to the ground as snowflakes! Frost is another form of ice crystals that you might see on windows and grass on early, cold mornings. To learn more about snow and ice crystals, check out our Snow and Hail issue of this newsletter.
How can you tell the difference between sugar and salt? They're both crystals and they look very similar - they are both white-colored, small grains. Of course if you tasted them both, you would know right away which one was salt and which was sugar because they taste very different. In this project you will find out how to tell sugar and salt apart just by looking at them!
Sugar and salt grains are actually tiny crystals. If you were to make a saturated solution of each of them, you would be able to see them grow into much larger crystals, but they would always have the same shape as these tiny crystals do! The salt crystals are cube shaped (like dice) and have six sides. The sugar crystals are very rough looking and are shaped more like rectangles with pointed ends. Most of the crystals are the same shape and size and look very similar to each other, but you probably saw a few crystals on your paper that looked a little different. Those crystals probably had pieces broken off of them, or there might even be more than one crystal stuck together, making them look different from the others. Also, the coloring of the crystals is a little different. Sugar crystals look very clear and sparkly while salt is duller and looks more white-colored or frosted.
Can you tell if the picture above is of salt or sugar? Highlight after this sentence for the answer: it's Sugar!