Make an igneous rock

Note: There are a variety of recipes for this on the internet. I have used several, most recently this one from The Accidental Scientist. It gives much more thorough directions and includes more details on sugar, crystals, and the rock candy process. My students and I have never really followed the directions to the tee, but eventually, we always get rocks.

This is part of a geology unit that focuses on the rock cycle. Creating rock candy is supposed to simulate the creation of igneous rocks. We create a solution, like magma, by boiling the water and sugar, then letting it cool. It usually takes a while for it to turn into a rock, so we introduced a new variable to see if rapid cooling made a difference.

Grade levels: 4-8

Problem: Which will make better crystals, a solution placed in the freezer or one that is air dried?

Hypothesis:

Experiment:
Supplies: Package of sugar, cups, water, pencil or straw, string, washer or fishing weight

Part I:
A) Bring 2 cups of water to a boil
B) Mix in 4 cups of sugar until it is dissolved completely

Part II:
A) Tie string to the middle of a pencil or straw.
B) Tie washer to the other end of the string.
C) Pour sugar water into cup.
D) Put one sample in freezer and one sample at room temperature.
E) Wait (It's going to take a while - weeks, not days).

(pictures coming)

Results:

	Freezer Cup	Room Temp. Cup
Observation 1
Observation 2
Observation 3

Conclusion:

Possible Errors/Things to look out for
1. Put wax paper or a towel over the top of your cups - mold will grow in them eventually.
2. It may take up to 4 weeks to actually see crystals, just let it sit.
3. Leave it in a lab, it will stink after a while.
4. I do this with 6th graders - they often have trouble tying the string on the straw.
5. Due to the mold factor, I wouldn't suggest eating anything that has been out for several weeks.