Page 13 - Curriculum Visions Dynamic Book

 This picture shows coastal salt pans.
The salt has been collected and formed into the white central pile. From there it is moved away by truck and train to customers nationwide.
Salt from the sea
brine: a solution of salt (sodium chloride) in water.
evaporation: the change of state of a liquid to a gas. Evaporation happens below the boiling point and is used as a method of separating out the materials in a solution.
pan: the name given to a shallow pond of liquid. Pans are mainly used for separating solutions by evaporation.
solution: a mixture of a liquid
and at least one other substance (e.g. salt water). Mixtures can be separated out by physical means, for example by evaporation and cooling.
 So-called “sea-salt”, obtained from evaporation, can be produced in large crystals. They are then ground down for use on the table.
Common salt makes up four-fifths of the minerals dissolved in sea water.
Salt has been collected since ancient times. To do this, people have used a method that copies the playas. They make shallow salt pans next to estuaries, each with a mud wall. Sea water is then allowed into the salt pans. The water evaporates under the heat of the sun, becoming very salty “brine”.
Gradually, salt crystals form and settle out at the bottom of the brine. The rest of the water, known as the bittern, is then drawn off and the salt is allowed to dry
off before it is scraped up and
carted away.
About 200 metres of sea water
have to evaporate in order to get one metre of salt, so getting salt from salt pans
is a slow process.
The crystals of salt that grow in salt pans are much larger than salt produced in any other way. This is why sea-salt crystals have to be crushed in a salt grinder.
 This picture shows an underground rock salt mine.
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