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So you are a crab! You live in the water most of the time.

What is SEAWATER?
(Adapted from information at http://www.marinebiology.org/science.htm)

Seawater is pure water plus dissolved solids and gases.

The dissolved solids come from 'weathering' processes of the land masses. For example, they may come from rocks that are dissolved by rain water. They then flow out to sea with the rivers.

The gases come from the atmosphere.

Many different compounds are dissolved in ocean water. The solid substances are known as 'salts.' They are made up of matter from living a non-living things. Their total amount in the water is called Salinity. Salinity may be different in different parts of the world. It is usually 34 to 37 parts per thousand. For example, a 1kg (kilogram or 1 thousand grams) sample of saltwater contains around 35 g (grams) of dissolved compounds.

Inorganic salts compose most of the solid matter of the 'salts' (99.28%). These percentages stay the same regardless of the water's salinity; therefore, salinity can be measured by measuring just the concentration of one of the salts, such as chlorine. You can measure the other compounds from there.

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Fill in the information in the boxes. To move from one line to another, press the TAB key on your keyboard or CLICK the next line with your mouse. (When you finish, print this page and place it in your folder. If you go to another page before you print, you will lose your information.)

What is seawater?

How do you think it is different from the water you drink?

What is "salinity?"

ADDITIONAL PRACTICE: Visit http://www.ksellars.demon.co.uk/Oassign1.html and complete the exercises on measuring ocean depths.

http://www.ksellars.demon.co.uk/marine_animal_project.htm

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