Growing Crystals Activity

Minerals contain tiny particles called atoms. The atoms in most minerals form a repeating, three-dimensional pattern. This makes a mineral grow into a crystal with a regular shape and flat sides. Some crystals form cubes. Others grow into columns with three or more sides. These are called prisms.

An example of a mineral that has cubic crystals is halite. A common name for halite is salt. This means we use a mineral to flavor our food.

Below is an experiment that you can do to grow your own salt crystals. There is also an activity page for you to cut and fold a cube that has the same shape as a salt cube.

Materials

glass jar
pencil
thread or string
salt

Procedure

1. Fill a jar half full with warm water.
2. Stir salt into the water until no more salt will dissolve.
3. Attach a thread or string to a pencil and hang it above the solution. Do not let the thread touch the bottom of the jar.
4. Observe your salt crystals each day. As the water evaporates, cubic salt crystals will form on the thread. Use a magnifying glass to examine the salt crystals. Can you see the cubes?
5. Crystals also come in other shapes. To study other crystal shapes, do the following:
   • Print out the crystal patterns.
   • Cut out each of the crystal patterns on the solid line.
   • Then fold along the dotted lines.
   • Tape the sides together.
   • Match the common crystal shapes drawn here with the ones you have created.

If you enjoyed this activity, you may want to visit this site to learn how to make Rock Candy.

You might want to invest in a commercial crystal growing kit like the one Preston used to grow his crystals.

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