|MadSci Network: Chemistry|
Hello Kayla, The iodine in the salt will act as an impurity that will cause defects in the salt crystals. This may lead to small and/or fewer crystals. If the salt solution is too hot, the iodine may color the salt crystals a light brown. The purer your salt, the larger and/or more numorus your salt crystals should be. Students have told me sea salt works best for larger crystal growth. Also any Kosher salt may work as well.
To check for impurities in your salt, dissolve an amount in water. Is the resulting salt solution cloudy? Or is it clear? Some ionized salt products have two to three impurities which tends to result in cloudy solutions.
The alkalinity or pH of the salt solution can effect crystal growth, but pH is hard to control. Hmmm. What happens if you dissolve salt in white vinegar? Does vinegar act as an acid or base and what is its pH? Does the solution grow crystals? Compare this to your crystals grown in drinking water and distilled water. Make sure a parent, guardian, or teacher is watching you mix the white vinegar solution, OK?
Another question you might investigate: What effect does the solution's temperature have on salt crystal growth?
Good Luck Kayla!
---* Dr. Ken Beck
Try the links in the MadSci Library for more information on Chemistry.