- Big Idea. Sodium chloride or common salt is the chemical compound NaCl, composed of the elements sodium and chlorine. Salt occurs naturally in many parts of the world as the mineral halite. Seawater has lots of salt; it contains an average of 2.6% (by weight) NaCl, or 78 million metric tons per cubic kilometer.
- Grade Level. High School.
- Time One 45 min. period.
- Content Standard. NSES Physical Science, structure & properties of matter: Bonds are created when electrons are transferred or shared among elements. Atoms or ions may bind together to form molecules or crystalline solids (e.g., salts).
- Ocean Literacy Principle. (1e) Most of Earth's water (97%) is in the ocean. Seawater has unique properties: it is saline, its freezing point is slightly lower than fresh water, its density is slightly higher, its electrical conductivity is much higher, and it is slightly basic.
MaterialsPeriodic Table; chemistry reference book or web access (optional); spheres of styrofoam, clay, etc. (some spheres should be about twice the size of others); student worksheet; toothpicks, straws, etc.
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