Grow Crystals

Grow Crystals

Grow your own crystal icicle using baking soda and water in about a week

Suitable for kids aged 5+ with parental supervision

You Need:
  • Two glass jars
  • Two paper clips
  • A length of thick woolen thread
  • Baking soda
  • Shallow dish
  • Spoon
  • Very warm water
What to do:
  1. Fill two jars with very warm water.
  2. Add spoonfuls of baking soda one spoon at a time and stir into each jar. Keep adding baking soda until you cant dissolve any more and you have a supersaturated solution.
  3. Attach a paper clip as weight to each end of the thick thread.
  4. Lower the paper clip ends of the thread into the jars so that it is suspended between the two.
  5. Place a dish under the lowest part of the thread to catch the drips. Let the experiment sit for several days and watch your crystal form.
  6. Try using other types of supersaturated solutions, like: sugar, table salt, borax, or Epson salts in water. Is there a difference in the formation of the crystal?

Why is it so?

Dripping water leaves great columns of minerals in caves over thousands of years. Those that form from the cave roof are called stalactites and those that form from the cave floor are called stalagmites.
In this experiment, the supersaturated solution (water cannot hold or dissolve any more of the solid) of baking soda soaks the thread and when it gets to the lowest point of the thread it drips. Each drip leaves a small amount of the baking soda behind. Drip by drip, the crystal icicle grows. After about a week youll have grown your own stalactite and, if youre lucky, a stalagmite rising from the dish.