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How to Grow Citric Acid Crystals

While rock candy is a favorite food-based crystal to grow, few young scientists consider growing citric acid crystals. The materials needed to successfully grow crystals are readily available at home, and in many educational supply or hobby stores. Citric acid granules are commonly found in the seasoning aisle of grocery stores or with supplies for canning preserves. Students will learn patience during the crystal-growing process because complete formation may take several weeks.

Things You'll Need

Crystallizing dish
Citric acid granules
Dowel rod
String
Masking tape

Instructions

- 1
  Boil 8 ounces of water and pour it into the crystallizing dish.
- 2
  Add one teaspoon of citric acid granules and stir. Continue adding granules by the teaspoon until the solution reaches saturation, when the granules will no longer dissolve. Observe carefully during this step, because if your solution does not reach saturation, your crystals will take longer to grow; if you supersaturate the solution, however, crystals will form on the undissolved citric acid granules.
- 3
  Drop two nickels into the dish if you want green crystals. If you do not add the nickels, the citric acid crystals will naturally take on a white tint.
- 4
  Secure a length of string to a dowel rod with masking tape and set the dowel across the top of the dish so it rests on opposite rims, ensuring the string is suspended in the solution.
- 5
  Observe crystal growth over several subsequent days. Citric acid crystals are safe to eat, but the taste is generally unappealing.

Rocks & Minerals