Subject: Are alum crystals supposed to grow bigger in cold places

I am in 4th grade and doing my science fair project on crystal growth and how 
temperature affects their growth. All instructions say place in a warm place. 
My hypothesis was that crystals would grow faster and bigger in warm places 
verses cold. This was correct for the salt crystal I grew, but I placed a jar 
with alum water in the refrigerator, with a string in the jar. I also placed 
the same kind of solution in a sunny window. The jar in the window had small 
crystals growing up the string.The jar in the refrigerator had nothing on the 
string, but crystals on the bottom of the jar. When I poured the solution into 
a clean jar, like the instructions said, I found very large crystals at the 
bottom of the jar. Bigger than my moms diamond in her wedding ring. Why did 
this happen? Was my hypothesis Wrong, or did I do something wrong. I don't know 
how to explain this on my conclusion.

Re: Are alum crystals supposed to grow bigger in cold places