Saturday, January 18, 2014

FTV January 18

Today the T.S. Kennedy continued on its path to Mayaguez, Puerto Rico, where we will do anchoring drills. We should be there by 0800 tomorrow morning and we will spend the whole day there. Once the drills are over we will remain anchored through the night and have a Sunday at Sea, which will provide a time for the students to relax, then we will head towards Haiti where we will deliver the supplies they are awaiting. Overall the cruise has been going smoothly and everyone has adjusted to the ship’s routine.

At our current longitude and latitude our typical view from the ship is miles and miles of ocean.
About 70% of the Earth is covered with water. Over 97% of that water is found in the oceans. Everyone who has taken in a mouthful of ocean water while swimming knows that the ocean is really salty!

Most of the salt in the sea comes from minerals that were part of the solid Earth (land!). When rivers flow over rocks on land, minerals get dissolved by the river water. These minerals are deposited into the oceans as the rivers flow into the oceans. The most abundant mineral in seawater is of course sodium chloride, or common salt
Ocean water is about 3.5% salt. That means that if the oceans dried up completely, enough salt would be left behind to build a 180-mile-tall, one- mile-thick wall around the equator! And more than 90 percent of that salt would be sodium chloride, or ordinary table salt. The oceans sure contain a lot of salt.

When we measure the salinity of water, we look at how much dissolved salt is in the water, or the concentration of salt in the water. Concentration is the amount (by weight) of salt in water and can be expressed in parts per million (ppm).
Here are the classes of water:

Fresh water - less than 1,000 ppm
Slightly saline water - From 1,000 ppm to 3,000 ppm
Moderately saline water - From 3,000 ppm to 10,000 ppm
Highly saline water - From 10,000 ppm to 35,000 ppm

Try this activity to find out how the amount of salt in the water affects its properties.

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