- Big Idea. Water has unique properties. About 97 percent of all water is in the oceans. Salt water or seawater has characteristics similar to fresh water with some noticeable differences because of the salts that are dissolved in water.
- Grade Level. Middle.
- Time. Up to three 45-minute periods.
- Content Standard. NSES Physical Science, properties and changes of properties in matter.
- 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.
MaterialsStation 1 (Boiling Point). Distilled water, seawater (or "Instant Ocean" mix from a pet store that sells salt water fish), isopropyl alcohol (optional), hot plate, 3 flasks with rubber stoppers that hold a thermometer, 3 thermometers that can measure from -10°C to 110°C, graph paper. Station 2 (Freezing Point). Distilled water, seawater (or "Instant Ocean" mix), isopropyl alcohol, 3 thermometers that can measure from -10°C to 110°C, 3 large test tubes with a one hole fitted stoppers, 3 Pyrex beakers, dry ice chunks, gloves, graph paper. Station 3 (Heat Capacity). Hot plate, 2 flasks (same size), 2 thermometers, bucket of ice water, stop watch.
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