12/07/11
Research Question:
How does the saturation of water affect the size of the salt crystals?
This project was chosen because it was intriguing and to find out if more salt equals bigger crystals.
Hypothesis:
If the water is more saturated then the salt crystals will be bigger.
The Independent Variable is the amount of salt in the water. The Dependent Variable is the size of the salt crystals. The Controlled Factors are the same amount of water, same type of salt, same temperature, and same preparation. There is no control group in this experiment.
Library Research: Crystals can form very quickly or can take thousands of years to grow, but all crystals are made of trillions of building blocks called atoms. Crystals are solid, geometric forms of minerals produced by a repeating pattern of atoms that is present throughout a mineral. A salt grain is made up of two atoms Sodium and Chlorine, which is called Sodium Chloride, it is the element NaCl. If you look at a salt crystal carefully you will see it looks like a cube because salt crystals are cubic but not all crystals are cubic, some can be triangular.
Salt crystals are cubic because salt is made of equal amounts of Na and Cl ions which are bound together by electrostatic forces, or opposites attract. The crystals wants as few nearest links possible broken so the best way for a salt crystal to be broken is one link per atom compared to the worst which is three links per atom. When a salt crystal is broken along its best planes it creates a perfect cube. Sodium crystals are made up of trillions of small cubes which then made a bigger cube. Each cube in a salt crystal is made up of four sodium atoms and four chlorine atoms, and all of the cubes next to it are exactly the same. What happens in water when you put in salt is the salt cells come apart and the sodium atoms and chlorine