Ocean Composition Chapter 13, Sect. 1

The Adventures of Huckleberry Finn by Mark Twain Summary: This famous story recounts the adventures of a young boy and a runaway slave on a raft floating down the Mississippi River. Excerpt:. . . It’s lovely to live on a raft. . . . Once or twice a night we would see a steamboat slipping along in the dark . . . and by and by her waves would get to us, a long time after she was gone, and joggle the raft a bit . . . Questions: Would it be easier to float a raft on salt water or fresh water? Did the egg float more easily in salt or fresh water?

The total amount of dissolved salts in water. Salinity The total amount of dissolved salts in water.

Variations in Salinity Near the surface, rain, snow, and melting ice add fresh water to the ocean, lowering the salinity.

Variations in Salinity Salinity is also lower near the mouths of large rivers, since they empty fresh water into the ocean.

What increases Salinity? Evaporation - salt is left behind as the water evaporates. Freezing – salt is left behind as the surface water freezes.

Effects of Salinity Freezing – ocean water doesn’t freeze until the temperature drops to about –1.9 degrees C.

Effects of Salinity Density – The mass of 1L of salt water is greater than 1L of fresh water. Example Egg Experiment.

Buoyancy – Salt water lifts less dense objects. Floating is easier. Effects of Salinity Buoyancy – Salt water lifts less dense objects. Floating is easier.