How to Make a Chemical Garden

Using different metal salts in a solution of sodium silicate to make different colored crystal towers that can be made to last indefinitely in the water.

This is an old trick that chemists like to perform especially in chemistry classes because it demonstrates several different types of chemical reactions and the results of these reactions. The reactions are crystal growing and precipitation caused when a series of metal salts are reacted with a dilute solution of sodium silicate. By using several different metal salts different colors are produced to grow into chemical towers up to 4 inches or more tall. By removing the sodium silicate solution from the crystal garden very carefully and replacing it with plain water just as carefully one of these displays can be made to last indefinitely.

To make a crystal garden you will need it least a 600 ml beaker or its equivalent. Cover the bottom with a thin layer of sand. Once the sand is in place you can add the sodium silicate solution that is about 25% sodium silicate and the rest is just water. This has to be added carefully so that the sand is not disturbed in the process.

Now we are ready to put the metal salts into place normally we’d just drop them in, but if you want to you can place them individually with a set of tweezers. The different salts produce a wild variety of colors.

  • White: calcium chloride commonly used for de-icing sidewalks.
  • White: lead nitrate is also used to produce white.
  • Purple: manganese chloride.
  • Blue: copper sulfate.
  • Red: cobalt chloride.
  • Pink: manganese chloride.
  • Orange: iron chloride.
  • Yellow: iron chloride.
  • Green: nickel nitrate.

It is best to use the chemical salts as large crystals rather than as a powder. This gives much better crystal towers in your chemical garden. Do not add too much chemical salts to the sodium silicate solution or you are garden will turn milky looking.

You can produce chemical garden’s using the chemicals that are listed above, but if you are of an experimenting bend of mind you can experiment with other metal salts. Most of the salts will react with the sodium silicate producing similar reactions. What you actually get are silicates of the various metals forming towers.

Warning: some of the salts are poisonous and we take no responsibility for how you use them. It would be best if these procedures were conducted by an adult rather than a small child.

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