Chemists study solutions to learn more about the materials around them. When the atoms or molecules of one substance dissolve into a liquid like water, that is a solution. How well substances dissolve is called the solubility. Try this experiment to learn what is and is not a solution.
You will need: two jars water table salt (NaCl) some dirt a magnifying glass a spoon
Fill the jars about half-full of water. Add a spoonful of salt to one jar and a spoonful of dirt to the other. Stir both and look at the water with your magnifying glass. What do you see? Do you know which is a solution and which is not? Why?
The salt molecules dissolved into the water. Salt is soluble in water. The dirt molecules do not dissolve. Through your magnifying glass, you can see that the pieces of dirt are suspended in the water, not dissolved. This is called a suspension, not a solution. What will happen after 30 minutes?
That's right. After some time, the dirt particles will settle on the bottom of the jar. They will not be suspended in the water. The salt particles stay dissolved in the water. Do you know a way to get the salt out of the water?
If you said "evaporation," you would be right. During evaporation, the water molecules let go of the salt molecules and go up into the air. The salt will stay behind in the jar. Leave the jar with salty water for a few days and see if you find the salt again.
Chemists use these ideas of solution and suspension. A substance that will dissolve in water can be made into crystals this way. We already tried that in another column. A suspension can be cleaned up some by letting the suspended particles settle and pouring off the top liquid. This process is one of the first steps in cleaning up your drinking water.
Now you know the solution! Look around for other solutions and suspensions.
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