Let's be rock gardeners. It will be fun to grow a large crystal in solution. We start with two cups of water in a glass container, and we will add 7 teaspoons salt, so as to
saturate the water.

We'll heat it until it boils, then add more salt until it is again saturated. Put it into the backs of your minds until it cools. After it cools, there will be salt crystals at the
bottom of the container.

We'll pour the solution through a filter to catch the crystals, and then divide the saturated liquid into several small jars.

Do you remember talking about a nucleus? It is like a seed, in that it forms a kind of core around which crystals can form. We will go to the filter, and collect the largest of
the salt crystals, and put one into each of the jars. We will leave the lids off the jars, so that some of the water can evaporate, and help the crystals to grow.

Again, let's filter the solutions and catch the crystals. We can tie a thread to each of the best ones, to hang in the jars. That way, the crystals can grow all around the nucleus; not just on the top and sides, which is the way it would be if the crystals were just sitting on the bottom of the jars.

First, we'll heat the solutions again, and add some more salt, to make sure the solution is well-saturated, then divide the solution into the small jars again. When the
solutions begin to cool, we'll hang the crystals in the jars.

Every day we will check our crystals, and make notes about the sizes and shapes, as they grow.

Good Grief! You don't suppose they will grow all the way out of their jars and join together and take over the world, do you? Maybe for English class we can write a science fiction story: "The Invasion of the Salt Crystals, Part I." The horrible salt crystals could march on the super-markets and take all the salt, so they could grow even bigger.

If any particles get into the solutions, the particles will become nuclei, and crystals will form around them. We might put a grain or two of sand into a couple of the jars, and see what happens.

If we aren't afraid they will take over the world, we can make the crystals grow even more by re-heating the saturated solutions, add more salt, and let the solutions cool with the crystals in suspension.

We could even put one of the jars into the refrigerator to see what happens. Maybe if it gets cold enough, more salt will come out of solution and form crystals.

Let's do it all over again, each of us having a jar with our name on it, and have a contest to see who can grow the largest crystal.

We could even use different stuff to saturate the solution, such as sugar, copper sulfate, Epsom salts, alum, photographic hypo, or Rochelle salt. The different materials
would probably make different shapes of crystals. Maybe even different colors, but we'll have to find out, because we don't know for certain.

When volcanoes make quartz crystals, the nucleus is sometimes gold! That's pretty exciting, isn't it?