The term "hard water" sounds sorta funny, doesn't it? Well, if you fall onto water from a high place, or from your water skis, the water feels really hard - almost like concrete. When you are swimming in water, or relaxing in the bathtub, it feels really soft.

When geologists and other scientists talk about hard water and soft water, they do not mean how it feels. Hard water is water with minerals in it. The minerals come from the rocks in the place where the water was before it came to us. A good place to find hard water is a stream with many rocks in it, or a spring emerging from rock.

Soft water is water without minerals in it. Rather than coming from under the ground, it comes from a watershed which is lined with leaves and stuff from a forest.

We've probably heard grown-ups complain about hard water; that it is difficult to wash with it, or maybe that it tastes funny.

Why would it be difficult to wash things in hard water? Perhaps hard water is not as good a solvent as soft water. Hard water does not get things as wet as soft water. Soap does not dissolve well in hard water; it makes a sort of scum on top, and if you wash clothes in hard water, using soap, you end up with dirty clothes with scum on them. Yuck!

Now that we've said all these bad things about hard water, we are going to make some hard water!

The drugstore has lime tablets, and the hardware store has lime. The school buys lime to make the white lines on the playing fields outside. It is that white, powdery stuff that they put onto the grass or dirt where they need boundary lines for certain games. We will mix it in with some water, and let it stand until tomorrow. The water at the top will be clear, even though it has lime in it. We will siphon it off into another container. Then, by bubbling carbon dioxide through the water, we will have temporary hard water.

Now, we will put water into another container, and mix in some epsom salts, plaster of Paris, or gypsum flakes, and let it stand overnight. Tomorrow, we will pour it through some filters (the kind used for making coffee will do) a few times, and we will have permanent hard water.

Let's put small amounts of the hard water into some smaller containers and see what we can dissolve in them. We can put some tap water into containers and dissolve the same solids in that, and see what the differences are.

We could wash our hands in the hard water, then in the softer water, and then we can feel the differences. I once bathed in the home of a person who had very soft water, and I felt slippery afterward. She explained that our bodies retain some of the soap we use when we bathe in hard water - it's that thing about hard water not being a good solvent. So when we bathe in soft water, that soap starts to dissolve and come off our skin. She said after three or four baths, one does not feel slippery any more, because by then, we are rid of the soap deposits. She explained it is the same with laundry.

Here is a surprise! I used to have great difficulty get the ice cubes out of the trays. I just didn't have the strength. When we moved from our former home, which was a very hard-water area, to an area with somewhat softer water, I noticed that I could get the ice cubes out of the trays with no difficulty. I certainly didn't get any stronger with the passage of time! Even though I believed it was very silly to wonder such a thing, I asked the resident geologist if hard water makes harder ice cubes than soft water ice cubes. He said, "Absolutely." "Do you know why glaciers are classified as rocks?" Well, of course I didn't know that. He told me that glaciers are loaded with minerals that they scrape up as they move along their paths. It is minerals that make water hard, and it is minerals that make glaciers become rocks.