In this experiment I plan to make a supersaturated sugar solution, in which large sugar crystals will form after the solution has cooled.
This phenomenon occurs because as a liquid is heated, the solubility increases, allowing more solute to dissolve. As the liquid cools, the solubility lowers and any excess solute in the solution crystallizes out.
Materials: pan, wooden spoon, measuring cup, string, ruler, jar, sugar, food colouring, water, a bead, scissors, time
Step One: I measured out one cup of water, and brung it to a rolling boil.
Step Two: Preparing the string- I attached a small bead to the end of the string, and measured the length out so that the bead was just above the bottom of the jar (about 11 cm). Then I dipped the string in a little water, coated it in sugar, and attached it to a ruler.
The bead acts as a weight to keep the string down in the liquid.
Step Three: As soon as the water started to boil, I began to add the sugar, one cup at a time and stirred the water until all of the sugar was dissolved. I continued to add sugar until no more sugar would dissolve; this created a supersaturated solution.
Step Four: After adding about 10 drops of colouring to the jar, I poured in the sugar-water solution. Since the sugar added volume to the water, I ended up with a little more than one jar would hold, so I used two!
Step Five: I placed the ruler with the strings attached over the jars so that the strings where hanging centered in the jars.
And now the waiting begins.
“It’s been one week since you looked at me”
One Week Later: The sugar didn’t quite solidify on the strings as I had intended. This is most likely due to the fact that I simply coated the string with sugar and didn’t allow them to fully dry. The sugar from the strings must have dissolved once they were placed into the solution. The dried sugar crystals on the strings would have created a place for the sugar crystals to begin growing. However, there was crystal growth on the surface of the liquid, as well as on the bottom of the jar.
After scooping all the solid sugar out of the jar, these are the ‘rocks’ I yielded:
In conclusion, slightly failed experiment, equally delicious results!