Science Buddies: "Ask an Expert"

HI, we just finished growing crystals in the three conditions of room temperature, refrigerator, and ice bath. We hypothesized the crystals growing at room temperature would be the purest clearest ones because we thought they would grow the slowest and therefore would have time to reject the impurities. Well, those did grow to be the clearest, however, they also seemed to grow the fastest. Should they have grown the fastest and should they have been the most clearest ones?

Chemical reactions and processes occur faster with higher temperatures so your results at room temperature are consistent with that fact. However, it is not clear why the crystals in the frig or freezer are not as clear. Having said that, my only thought is that something (food, odors, etc.) in the frig or freezer is being combined with the crystal matrix causing lack of clarity. I hope that helps.