"The word dissolve means to loosen or separate," replied Norah. "The water has the power to loosen and break up, or separate the solid salt into such tiny little particles that we cannot see them. Whenit is broken up into these tiny particles, we say the salt is dissolved. The water cannot break up the coal. It will not dissolve.""Do you know what we say about the salt because we can dissolve it in water, Norah?""We say," replied Norah, "that the salt is soluble. The coal is insoluble; that means not soluble.""What other substances will dissolve if we put them in water?""Sugar, soda, alum, and lime all dissolve. They are all soluble substances," said Norah.
"Now tell us what we say about the water that dissolves these things?" said Fred.
"We say that water is a solvent for sugar, salt, alum, lime, and any of the things which it dissolves," said his sister.
"See," Fred continued, "I can take the coal out of the water just as it was when I put it in. But can I take the salt out in the same way?""No, the salt cannot be taken out, because it is broken up into very small particles, and the particles are scattered through the water.""Could I get the salt out of the water in any other way?" asked Fred.
