While reading a paper about ice crystal growth, they use vapor and seed to create crystal. I thought that I could observe crystal just by freezing liquid water. Is there differences between just freezing liquid water and using vapor and seed?
1 Answer
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The seed is important. It is a small crystal that gets larger. It can be difficult for crystal growth to start. A tiny crystal about a nanometer across has a very large surface compared to its interior. Surface atoms have different bonds than interior atoms. Sometimes it takes more energy to be on the surface. This makes a tiny crystal energetically unfavorable.
Because of this, crystals tend to start growing on a surface rather than the center of a liquid or gas. This can happen multiple places. Then you get multiple crystals in different orientations.
Under controlled conditions, a seed ensures that only one crystal forms.
A liquid is either present or not. Gas can be present in high or low concentration. Concentration has an effect on how the crystal grows.
Snowflakes have many different forms. Which form is favored is determined by concentration and temperature. See http://www.snowcrystals.com/science/science.html
answered Feb 25, 2017 at 16:40